I had intended to find an answer (at least enough of an answer) to the question in the post title and write it in this article. But I find that I can't answer it in a timely fashion, and think it is interesting to post some of my process as I seek an answer. So this post ends with different research directions I could go, rather than answering the questions developed in the body of it.
It's rational to take into consideration the greatest threats to human well-being and then try to avoid them, even if they are relatively unlikely. Annihilation is a threat worth avoiding, but even more so is eternal conscious torment (ECT). If this is the case, then if there is some proposed worldview that contains ECT, we should have to adjust our behaviors to fit it, (almost) no matter how unlikely it is -- unless we can come up with a defeater for that practical belief. ("Practical belief" being something that is believed in by action, whether or not we are fully sure of it epistemically.)
There are a large, potentially infinite, number of worldviews that propose ECT, but if their likelihood is all Pascalian, then we can't practically worry about them, because they cancel each other out. But suppose there is some religion X that proposes ECT (let's say, an analog to the Invisible Flying Spaghetti Monster that gives those who do not eat the dishes it approves of horrendous food poisoning for all eternity). Let's say we have some small amount of rational evidence for its truth, which pushes its credence above the Pascalian, into the non-Pascalian. So now, are we practically obliged to observe the list of approved foods (which is heavy on pasta)? Is its food poisoning a strong enough consideration to swamp whatever good comes from committing to the God of MSLN? Sure, MSLN's God promises eternal life. But how can the promised reward of eternal life compare with the promised threat of eternal food poisoning? (And of course, the Stringent Invisible Flying Spaghetti Monster (SIFSM) offers a paradise of delicious pasta dishes and also transcendent high-qualia-of-ought-to-be-ness-inducing salads, for all eternity, a reward which easily equals any similarly hedonic heaven that God could offer.)
The threat of ECT is worth considering, no matter how little evidence there is for it, provided there is some. So how can we parse this situation? Do we have to let ECT dominate reason? We might be 99% sure of the truth of MSLN, but only 1% sure of the truth of SIFSM, and strangely enough turn away from and fail to trust the God that is very likely to exist for the one who is very likely to not exist, just because the expected (dis)value of ignoring the unlikely one promises to be so high. This does not seem like an entirely desirable situation to be in, from the standpoint of the intersection of good practice with good believing. Is there some kind of "practico-epistemic" (to coin a word that perhaps doesn't need coining) filter to keep us from having to act as though we believe in just any even-barely-non-Pascalian ECT worldview?
Here's one way to try to get out: Christianity, for better or worse, has had on the books some kind of ECT doctrine for its entire existence. It's debatable whether the Bible really teaches it, but for the purposes of this, just that it is debatable is strong enough. The evidence for Christianity is considerable. Hundreds of millions of people perceive it to be true, and perceive that its God exists. The only competitors to it on that scale are the worldviews of Islam, Hinduism, Buddhism, and secularism. Certainly some upstart like SIFSM doesn't have that level of witness. This traditional Christianity threatens a hell that is just as bad as the worst conceivable food poisoning, for just as long, all eternity. So it has the same penalty, but is more likely, and therefore dominates SIFSM, practico-epistemically.
However, now we have to set ECT-affirming Christianity and ECT-affirming Islam side by side. So how can we tell what to do? Should we form a saving relationship with Jesus, God who became a man, son of God? Or with Allah, the one who has no equals? Arguably, the penalty and reward for both are both infinite and equal, ECT and paradise. Now how can we tell which one to favor practico-epistemically? Are we reduced to flipping a coin and hoping for the best?
At this point, I would like to bring in MSLN and say, "look, MSLN can give us a lot of evidence in favor of Christianity, so we should favor ECT-affirming Christianity". On some level, this makes sense. In a religious sense, I (as an MSLN Christian) feel more kinship with those ECT-affirming Christians who are really shaped by Jesus' teachings than I do with Muslims. But, is it really "legal" to use MSLN to do that in this case? MSLN rules out ECT. So if the idea is to have a Christian worldview that teaches ECT which logically dominates all the others which teach ECT, so that people can pick one right (hell-safe) worldview, can we support that worldview with auxiliary arguments that deny ECT?
I'll step back for a minute and consider, what's at stake here? If people don't believe Christianity is true, there is some increased risk of them not accepting Jesus in this life and going to a hell of ECT (traditional, ECT-affirming Christianity) or becoming hardened to the voice of Jesus in this life or in the Millennium (New Wine Christianity). If they don't believe SIFSM is true, perhaps they are similarly at risk of ECT. SIFSM seems exceedingly unlikely to me (especially because I haven't found any arguments in favor of it, have only just asserted the image of it -- it only hypothetically has evidence in favor of it). But because it favors ECT, it can seem like a greater threat than the far more likely MSLN. If people did not put their practico-epistemic trust in MSLN, in favor of SIFSM, and they took this to an extreme, completely turning toward SIFSM and away from MSLN, they would probably be annihilated, all to avoid a distantly-likely infinite threat.
One natural way out of this is to say "Okay, I'm pretty sure that MSLN is true, but I'll stay away from those forbidden dishes. Who knows, maybe I can keep from experiencing eternal food poisoning that way". However, when we bring in something like Islam into the picture, we now find ourselves practico-epistemically encouraged to... worship both Allah and Jesus? In the old days, the people of God often tried to do that kind of thing, and God was not happy. Somehow God expects us to be able to figure out that he's the one for us without us betting a little in favor of the saving power of all the others. This exclusivity over against hedging is something that I expect is operative in Islam as well.
One "supernatural" way out ("supernatural" in a Weilian sense, maybe), is to say that ECT and annihilation are red herrings. Hell is a big distraction. True well-being is to love. Even if you get trapped in ECT, if you really love, then you are truly fortunate. So if we're weighing Likelihood against Threat, ask yourself if the threats even matter. Annihilation prevents you from loving, but ECT does not (arguably). Neither of them prevent you from becoming a loving person "NOW", in this life. In the book of your life, you can always make the best choices you can. Perhaps even likelihood can be ignored (at least as an absolute in determining practical epistemology), and all that's left is to say "what is genuinely beautiful, and more important than that, what is genuinely true? If I'm not looking for what is true according to my own fears, desires, etc., but only for truth in itself, what do I see?" Likelihood has some connection to that, but threat does not.
And yet what is love if not (in part) to protect others (or yourself) from threats? Maybe the real threat is to not learn to love "NOW". This is in keeping with MSLN. But hell (historically, the threat of ECT; or in MSLN, the threat of punishment and annihilation) is a useful doctrine (and reality) in helping some of those at greatest risk of hardening to turn toward God. We don't necessarily all value love of God for itself at first.
What this might mean is that for some, hell is and has been convincing in a way that leads them to love God, so it's a good thing. But for those who understand somewhat more, it creates issues such as the possibility of something like the SIFSM. But then those who understand more than that see that Likelihood dominates Threat, when we define the real threat to be not being in line with the truth that is orthogonal to well-being, which turns out to be God.
This all has some bearing on how to understand the metaphysical organism argument. Part of that argument says that there is some (I would now say "non-Pascalian") chance that God exists, given the issue of consciousness vs. matter and how there's some reason to think that the Metaphysical Organism's existence could settle it. So we should act like God exists, if it is not costly. But should we act as though the Father, or Allah, or Krishna, or the SIFSM, or...? exist, based only on the metaphysical organism argument? One action that argument recommends is prayer, as well as a "costless" trust. Do we pray to all of them, or trust in all of them? Arguably, to fully trust God, we must go all in on some path of trusting him. But the metaphysical organism argument, by itself, does not warrant us choosing any particular God (so long as that God conforms to the description of the Metaphysical Organism -- currently, of the gods listed above, only the Christian Father as found in MSLN / the New Wine System fits the description). So if we are MO-only believers, we should pray to "the true God, whoever you are". That way, whatever God really exists, we will have been praying to him/her/etc. all along. That God will want us to understand him/her/etc. better and provide ways to do that, when the right time comes.
But then, I keep thinking, isn't either a Muslim or Christian ECT possible, and shouldn't we warn people away from it? I am okay with saying that my own eternal well-being is less important than seeking what is true apart from Threat, and learning to love no matter my experiential circumstance. But what about other people's eternal well-being?
So I think there could be more thinking done here.
One possible route is to explore if there are non-MSLN reasons to prefer either ECT-affirming Christianity or ECT-affirming Islam (or some Hindu or Buddhist equivalent?). This sounds like a lot of work, to understand these religions enough to say one is better than another, and is not my first choice to find an answer here.
A second possible route is to consider the possibility that Reformed epistemology is invalid, or not valid enough. Reformed epistemology says that we have noetic perceptions of God, and those beliefs are good enough to make the resulting beliefs in God rational, for some definition of "rational". Presumably Muslims have noetic perceptions of God. Do we have any solid evidence for revelation (the Bible or Quran) apart from "faith" (a belief produced in us supernaturally by God, which is itself a perception of God)? This version of "faith" may turn out to be in a Pascalian situation (there could be as many believable gods as there are people who bother to invent them), and if so, we have no reason to trust either the Bible or the Quran as revelation, just from that "faith" belief. So whatever the books say about ECT isn't something that can threaten us. Then to choose between the two, we would look to some kind of reason, perhaps a natural theology like MSLN, to choose which one to follow.
(One could say that perhaps Christianity and Islam contain within them people who have these arguably-supernatural "faith" beliefs, but that these beliefs do not arise on command for some religion-inventor. But in the future, maybe we will be able to engineer such belief-experiences, which will be taken as the occasions for God (or the IFSM or SIFSM, etc.) to touch our minds. So then we will still be able to invent some kind of reason to believe in whatever beliefs a religion can contain.)
Or is it possibly the case that both Christians and Muslims see God noetically, and are seeing the same being, whose real nature they disagree about, but neither of them noetically see (with the same justification as the "basic belief" in God) that ECT is valid? (ECT in this scenario would have to be something added on, by certain readings of the Bible or Quran, to the basic undifferentiated theistic faith derived by noetic perception.)
If we are in a basically Pascalian situation with respect to ECT, we will need stronger evidence (Likelihood) to get an answer of what to do, practically.
I would think it very strange to think that noetic perception is not at all valid, and that if it is valid, that perceptions of God (or of anything) in a noetic way yield absolutely no evidence that such things are real. But on the other hand, while I found Reformed epistemology (my source for the concept of "noetic perception"; as read about in Plantinga's Warranted Christian Belief) to be helpful when I was younger, I also found it vaguely dissatisfying, and perhaps at this point in my life I would be better able to figure out why. Exactly how far can noetic perception go? Does Reformed epistemology equally justify Islam (or other belief systems)? Re-reading Warranted Christian Belief was already seeming interesting to me, and this is another vote in favor of doing that.
The third route to go is to explore, just what are the "axioms" of ECT? What are all the truths that must be true for us to even have the situation of being threatened by ECT? And then, once we have identified those truths, what else do they imply? In math (if I understand correctly), if you properly understand addition, you have to understand some basic axioms. Then, once you understand those axioms, you can build new things, which are not addition, and which you couldn't directly get from addition. But (I think) the validity of addition implies the validity of the things derived from addition's axioms. This is the most attractive of the three routes (as of today [the day I wrote that draft]), and so I hope to have something to say on the topic in a later post or posts.