Not sure ubisoft works for your vision of playstation at least in the short term, 33 of their revenue is on Sony platforms, 8 is on mobile and 58 is on other platforms.
I can't see Sony buying them and then killing the majority of their revenue stream in the hope they increase revenue on the Playstation platform.
Yeah, I doubt they'd go for them... they are not really central to the PlayStation brand. Even though they seem like a deal right now.
Square and Kadokawa make the most sense with them both having interests in gaming and anime / manga and film.
Arc System Works too..... just works with anime / gaming crossovers.