No Joshy...non-canon Monica/Jenna/Katie ending. There will be no full harem ending, canon or otherwise. As Cheeky said, completely defeats the point of his story and choices/consequences.
I stopped playing a full 18 months or so ago because I found out there wouldn't be a true Harem ending, I was sorely disappointed and most all interested to be honest, I had and have no interest in an ending were I can't see all the women get along and have the MC's babies.
It feels like such a waste to attracted to all the girls and get to know than throughout the story just to have to break up with them later. Yeah nope I don't want to invest more time into character I'm not going to be able to end the game with and I don't enjoy playing a game 2 or 20 different times just to experience a different ending.
Especially if and when a game experts me to reply the entire game again just to experience 5 a few different dialogue lines here or there but it's mostly the same otherwise, that's like re-watching a movie for the end of 3rd time just because they changed a line or added a deleted scene... It's not worth it.
I don't know how this game will handle the multiple ending in terms of how far back we have to go in the save files or whatever but I have up on this game, it killed mu interest by not having a true harem ending.