>>715916690 (OP)
So while it may seem silly to talk about a timeline/canon for a game series and its spin-offs that really doesn't take itself seriously and seems to frequently ignore world building just because (something about the Wario games don't really seem to fit with Mario's world), but yes, Pauline's age in Bananza does open up a can of worms than the typical liberties taken in the Mario franchise.
Pauline in Banaza is (by all implication) the same character as Pauline in Odyssey but younger. However, Pauline in Odyssey is in turn also implied to be the one from the original Donkey Kong arcade game and Cranky still implies he is the Donkey Kong from the arcade game, with several other things implying that all the Rare developed games also happened. And there is no indication that Pauline is de-aged or anything, so that's out the window.
So Bananza can't be a prequel is Cranky is indeed the original Donkey Kong, but since Pauline was an adult even in the original game it can't be a straight forward sequel either... The only explanation that makes any sense is that the implication that Pauline is the same Pauline we've always is seen is a mislead, and in actuality she's a different character.
