As someone not too deep into Megaman and got introduced to this mod by a friend, it's amazing and growing on me!
That said, we've encountered a few minor bugs that aren't anything game-breaking, but are probably easy to miss so I'm pointing them out.
One is if a character loses their cap but manages to get it back right afterwards (Ie. getting blown away by Big Snowman,) the game might still treat them as missing their cap. Cycling through and switching in Character Select as well as toggling the cap with Z in the player option of Coop menu appears to work as a sort of bandaid. Worth noting I've only lost my cap once, as Gaea X, I can't say whether or not this applies to all characters in the pack.
Another bug is if these characters get burned by fire. The effect of it is prolonged on them reducing them to at least half of their health instead of the normal -3 health points, and sometimes persists even longer quickly reducing great chunks of health. This doesn't include getting burned by lava as that instance seems to work just fine (gotta love Gaea X's lava resistance)
I just wish that visually it was easier to tell if they're missing their cap, but I'm not gonna complain on that when it's a pack that is in progress and still getting updates.