Not only is Pauline back, not only is that song above actually sung by her, she's no longer just a famous star, she's the mayor. Pauline's got more development in this game than Peach has in the past 7.
The game looks pretty great as we've been saying in the main thread, but yeah, Pauline is mayor now and has character progression. That's great. I don't know if you can take her over, though... maybe? You can possess at least some humans, anyway.
On the note of Peach though, there's a big contrast between the tougher Peach of Mario & Rabbids and the usual useless kidnappee of Mario Odyssey, that's for sure, and Odyssey does not look good in comparison story-wise.