I'd rather wait until the episodes start pouring in.
There was a LITERAL SOURCE saying they will age up in season 5. Go check the Season 5 (The Loud House) before you do any edits IAmMaxB. No one will revert any edits since they already confirmed they will age up.
I don't think they can be classified as antagonists. The only antagonist of the episode would be Luan as she was the one pranking the Louds and she used the Doubles to do that. That doesn't make them antagonists, that makes them tools of the anatagonist.