Jayce
Nidalee

Play the laning phase relatively passive and stalemate them whenever they go for any sort of objective push. Have your Jayce go relatively tanky so he can be your hard engage, and just poke them out with spears + Jayce Q before you fight, you have Nid heals for indefinite sustain as well so you'll simply out last them. Once you hit 25+ min.s 2-3 Nid spears = a won fight even if they stack MR.

EDIT:
BTW you can also have Nid set up trap walls in mid so you have no excuse to ever get caught.

PS: I don't know if you know to do this but you should be banning Cho'Gath in 100% of matches, his late game scaling is far too strong in situations with low numbers of players.

I feel like your statement is only applicable to the tanky SR build for Cho. If you build Cho Tanky AP he is a terror.

RoA > Guise > BFT > Abyssal/Wooglet's > Void

He'll do as much, if not more damage than, your average AP and his ultimate will be putting out true damage to the tune of nearly, if not even more than, 1,000. (The CDR from BFT and presumably masteries, makes his CDs frighteningly short and depending on opposing comp, he can 2v1 in a concerningly high number of situations.)

All those things apply in 3v3 making Cho a high tier 1 if not god tier in most players' opinions, and they don't change if you remove a player.

You can also just go champions that win lanes no matter what situation.

Elise and Darius if you can get them