not doc or mario though, probably marth would be a good choice to go, maybe falcon too, since fox-falcon is a very common combo, kinda like doc-ganon-ICs seems to be pretty common also, either that or fox-falco
whatever you want, preferbly someone to counterpick doc and mario since they will be your toughest match-ups, so preferbly falcon or marth are your best bets since they are the marios worst match-ups and they both are fast, marth is easier to use but falcon is faster, so which ever you want, marth probably is safer because he does better in tournaments and your fox isn't doing so great so i would say, try marth but fox is solid enough in which you can go all fox