Both pages will receive the same updates. Current 0.31 version is the same on both of them.
This page exists just because the original one does not appear on the “most recent” category when I update it (it should). I’m trying to figure that out still.
The game now is not like dating sim, so there is no main char, instead you play the mini games and open content with them.
About purchasing multiple times, as far as I know, itch remembers the amount you’ve donated on the game page and if the price doesn’t change, you don’t need to pay again. Unfortunately, I haven’t really encountered with feedbacks about that, so, I might be wrong.
The price will not change for at least 3 more major updates. I didn’t think about it further.
I hope this helps.