Three of your projects rank highest on personal interest. I think I would attempt a more granular analysis of this keeping in mind your current uncertainty about your model of your maintained future interest.
Some ideas:
Pretend that you are handing off the project to someone else and writing a short guide to what you think their curriculum of research and work will look like.
Brainstorm the key assumptions underlying the model that assumes a value for each project and see if any of those key assumptions are very cheaply testable (this can be a surprising exercise IME)
Premortem (murphyjitsu) each project and compare the likelihood of different failure modes.
Three of your projects rank highest on personal interest. I think I would attempt a more granular analysis of this keeping in mind your current uncertainty about your model of your maintained future interest.
Some ideas:
Pretend that you are handing off the project to someone else and writing a short guide to what you think their curriculum of research and work will look like.
Brainstorm the key assumptions underlying the model that assumes a value for each project and see if any of those key assumptions are very cheaply testable (this can be a surprising exercise IME)
Premortem (murphyjitsu) each project and compare the likelihood of different failure modes.