cause the amount of fat Square themselves are cutting
Or maybe that's just because they want to be a more efficient 3P multiplatform publisher?
it means Final Fantasy is now a Sony IP
No, this is cap. Square-Enix owns the Final Fantasy IP, not Sony. And with today's news, it's highly likely at least Switch 2 and PC/Steam will get versions of FF VII and XVI. Even Xbox will likely get a port of XVI at this point at least. Just because the games have released on PS consoles first (with shrinking exclusivity windows) doesn't mean they're Sony IPs.
and they can turn it into a multi media franchise
They could still do that. Though really, with the way things seem to be going I'd rather Sony bring back a couple of their own JRPG IPs, and build those up in both gaming and with transmedia stuff (like original anime & manga series).
Square-Enix doesn't need Sony to make FF more multi-media an IP and Sony/SIE can use their money to better enable their own equivalent IP forward (and have a replacement for FF that's a JRPG exclusive for PlayStation).
I would rather they do the same thing you said in your last paragraph but the narrative that they won't be acquired is off basis when they're showing everything Sony's new strategy is going to entail going forward tbh
So you're okay with Sony's multiplatform strategy? Because I'll be honest: I'm not. This PC strategy of theirs has left the console with very few actual exclusives, with PC gamers getting the better end of the deal as long as they have a bit of patience, and as time goes forward they may not even need that patience. Smaller windows of exclusivity for 1P games means the same thing with 3P exclusives.
Day 1 PC for all 1P games means you can kiss PlayStation 3P exclusives goodbye. Which is exactly what people like Paul Tassi, Micheal Patcher, Destin, Colteastwood, Ryan McCaffrey, Bloomberg Takashi, or places like ResetERA, XboxERA etc, or other platforms like Steam, want. That's why they're constantly encouraging Sony to put their games on Steam and do away with staggered releases. Maybe that strategy works for a 3P publisher, but it kills a platform holder who has hardware to sell.