Random thought after seeing 4th character speculation (not that there's any sign of one coming for sure…
.
Just curious, but what do you mean by 4th? Ah wait, you must mean in terms of DLC; I see.
I completely think that any additional character that will be playable will be involved with the story, as it has been for everyone else. Another character (whether DLC or unlockable) isn't completely out of the question, but I think there's absolutely no way it's a P1 or P2 character. I was close to saying the same for Margaret in the past, but that would be on another level completely.
Edit: I have no idea if one last character would be
him or not, but there are still a few potential indications that there
could be another, though they're way weaker than stuff like the 2 DLC cards after #035 (which obviously turned out to be for Marie and Margaret). There's the potential character screen layout I came up with that would solve certain incongruities and the 3-4 remaining weeks of updates, while there would only be 2 character trailers left (with Mitsuru potentially being combined with Margaret's in a single week), but those are essentially nothing.