Sorry, but I simply cannot see Square pushing for Geno...at the end of the day SMRPG on Switch is a remake that doesn't promote any of their own IP. I would guess that Square would probably prefer just about anyone else of theirs.
Not that Square would be able to get whoever they want in, anyway; the characters are chosen by Nintendo/Sakurai.
I think the remake does more than that. It is not it being a remake that matters, but what game it is, and despite it being released at the end of the SNES' lifetime and not being released in Europe, Super Mario RPG is a classic, and it was very well liked, and that includes Geno, who was well liked too, among other things, so the remake definitely helps.
Still, I can acknowledge other things...
...Just like how a physical force hinders an object from accelerating forever in physics due to forces on the object balancing out, a remake only does so much, even for Super Mario RPG. I mean, that and other things can and do limit how the remake can affect Geno's chances, so it is safe to say that a remake can only do so much.
But anyway, I did hear that the creator of Super Mario RPG did want to do a sequel to that game, so if Geno does not really get in the next game, a possible Super Mario RPG sequel, if made, can give Geno an extra chance, if just one more.