you appear to have missed the point of my reply.

Let's check: "I can only have preferences over things that exist. The ship probably exists, because my memory of its departure is evidence. The parallel worlds have no similar evidence for their existence." Is that correct paraphrasing?

Before the ship leaves, you know that sometime in the future there will be a future-ship in a location where it cannot interact with future-you.

By the same token, you can observe the laws of physics and the present-state of the universe. If, for some reason, your interpretation of those laws involves Many Worlds splitting off from each other, then, before the worlds split, you know that sometime in the future there will be a future-world unable to interact with future you.

For future-you, the existence of the future-ship is not a testable theory, but the fact that you have a memory of the ship leaving counts as evidence.

For future-you, the existence of the Other-Worlds is not a testable theory, but if Many-Worlds is your best model, then your memory of the past-state of the universe, combined with your knowledge of physics, counts as evidence for the existence of certain specific other worlds.

In your Faeries example, the Faeries do not merit consideration because it is impossible to get evidence for their existence. That's not true in the quantum bomb scenario - if we except Many Worlds, then for the survivors of the quantum bomb, the memory of the existence of a quantum bomb is evidence that there exist many branches with Other Worlds in which everyone was wiped out by the bomb.

So, the actual question should be:

1) Does Many-Worlds fit in our ontology - as in, do universes on other branches constructed in the Many-World format even fit within the definition of "Reality" or not? (For example, if you told me there was a parallel universe which never interacted with us in any way, I'd say that your universe wasn't Real by definition. Many Worlds branches are a gray area because they do interact, but current Other Worlds only interact with the past and the present only interacts with future Other Worlds, not current ones )

2a) If we decide that the Other Worlds from Many Worlds qualify as "Real", can Many Worlds ever be a hypothesis which is Parsimonious enough to not be Pascal-Wager-ish? The Faeries qualify as "Real" because they do cause the raindrops to fall, but because of the nature of that hypothesis it can never be parsimonious enough to rise above Pascal-Wager-thresholds. Is Many-Worlds the same way? (From your answer, I gathered that your answer is "yes", but I disagreed with your reason - see paragraph that begins with "In your Faeries example..." which is why I pointed out that if you accept Many Worlds then you can have evidence that points to certain sorts of worlds existing in my first reply.)

2b) If we decide that the other branches do not qualify as Real, can we make a definition of reality that does not exclude light-cone-leaving-spaceships?

3) And how do we construct our preferences, in relation to what we have defined as "Real"? (For example, we could simply say that despite having an ontology that acknowledges all the branches of Many Worlds as Real, our preferences only care about the world that we end up in.)