This seems then closely related to the much more general question of what makes counterfactual statements true or false. Like ones of the type mentioned in the last bullet point above. For descriptive statements, the actual world decides what is true, but counterfactuals talk only about a hypothetical world that is different from the real world. In this case, the difference is that I know (in the hypothetical world) all the consequences of what I want. Of course such hypothetical worlds don’t “exist” like the real world, so it is hard to see how there can be a fact of the matter about what I would have wanted if the hypothetical world had been the actual one. The answer might be similar to what you are saying here about fictional objects.
This seems then closely related to the much more general question of what makes counterfactual statements true or false. Like ones of the type mentioned in the last bullet point above. For descriptive statements, the actual world decides what is true, but counterfactuals talk only about a hypothetical world that is different from the real world. In this case, the difference is that I know (in the hypothetical world) all the consequences of what I want. Of course such hypothetical worlds don’t “exist” like the real world, so it is hard to see how there can be a fact of the matter about what I would have wanted if the hypothetical world had been the actual one. The answer might be similar to what you are saying here about fictional objects.