The 3player and 4player category thing that multiplayer 2 player 3 player 4 player is all in one category there's no need to put them in other categorys but multiplayer cannonless and 100% if u do a run of it it could be a category I'm not to shore u need to ask the mods

Multiplayer categories already exist under the miscellaneous tab. 2 player, 3 player, and 4 player runs all go there. As for cannonless and 100% multiplayer, there was a 100% multiplayer on the category extensions board but nobody ran it (the people who did din't even submit) so it was removed. Unless there is a lot of interest in it, it wont be added. (Also reminder that Romain isn't the only mod, there's 5 others)