I need C.Falcon's bad matchups (apparently zoning characters) and who covers them, please.
Pikachu and Sheik are his worst MUs in my experience. They tend to dominate the neutral against him pretty easily and can zone and outspace him out to avoid most of Falcon's approach options. Falcon's subpar ground game also add to these factors. Both have amazing offstage game as well: with CF's average recovery, he's easily gimpable.
Pikachu has the insane mobility, speed and a decent projectile so CF can't really go ultra agressive against him, has issues with punishes because of Pikachu's super safe moveset, and has issues comboing him because of his small model.
Sheik is pretty obvious but well she has the freaking needles - which is most likely the best projectile of the game - and outranges most of Falcon moves. Also Falcon being a fast faller + heavy character makes him a super easy target for Sheik bread and butter combos. Needless to say, Sheik's frame data is close to flawless so the punish game for Falcon is even harder than Pikachu.
If you are talking about doubles options for coverage I'm afraid I don't have enough knowledge of 2x2, but the Mario bros usually counters Pikachu decently (especially Luigi). Sheik, well... good luck.