In regards to Canon AUs, and Katekyo Hitman Reborn! canon specifically, is it acceptable to play a character from a Post Canon Ten Years Later perspective rather than the aborted/fixed Millefiore War timeline?

In the same vein, given the lack of explicit information about the Acrobaleno would it be more acceptable to play one pre-curse, with headcanons of past, or post-canon post second growing up a second time?