Personally, I think P5P makes a lot of sense and is something we could see in a couple of years, regarding P Studio. I don't think it is at all, however, a sure thing.
SMTV and the recent Dancing and Catherine announcements suggest that Atlus believes in putting out ecosystem exclusives (to this point, Catherine was originally on X360, no? Isn't this new version Vita/PS4?) and we could instead just see an enhanced edition for PS4 in a couple years instead of a portable edition.
I think, more than making SMTV multiplatform, which I think would be a good idea and could ride P5's coattails on PS4 some while also going for the Atlus fanbase on (Nintendo) portables, P5P makes a lot of sense given the importance of, in particular, Golden to the growth of the franchise. There's a track record of success for portable Persona re-releases and it isn't like Atlus doesn't sell on Nintendo platforms--they do. Beyond this, Persona just has a higher sales potential and more to gain from multiplatform accordingly.
So I think what does end up happening wrt a hypothetical Persona rerelease will be incredibly telling as to Atlus's future release strategy.
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This would be the ideal for Switch (everything :P) with my thoughts on each piece:
-SMTV--this is happening
-successor software to other 3DS games, including new SMT spinoffs and other new/old RPG IP from said software streams--currently, 3DS is still getting these games and there would at least be problems transitioning EO. I think we will see these support streams on Switch, albeit after a wait and at diminished productivity.
-TMS successor--I think this was made by a team that worked on 3DS though? So this might just roll into the above. I could see more things like this though, with Nintendo paying to offset increased development costs.
-Persona 5 rerelease--I assume a release is happening and atm I'm hedging my bets towards PS4-only release, personally.
-Persona spinoffs/other P Studio software going forward--currently this is skipping Switch and until we see signs otherwise, I'm going to assume it will continue to do so, outside more PQ. (Higher chance of more coming if mainline Persona comes).
-Project Re: Fantasy--I'm guessing this will follow Persona support, whichever way that goes. So I'm guessing PS4 exclusive atm, but I could see it being multiplatform or having a late Switch release (perhaps enhanced).