3 Rams, 2 f 1m same with the Apistogramma species. Might be pushing it with a pair kribs, you wouldn't want other fish in the tank in this case.
No special set up. For kribs and apistos I have some small terracotta flower pots on hand that I make caves with. I have kept these fish in a low-medium light planted tank with Val, Anubia, Java fern, crypts and carefully selected amazon swords.