I had 2 kribs in a 30 gal tank. my (ex) gf brok her tank and i adopted her fish. her female betta and the kribs did not get along at all. they'd constantly chase her, she'd spend like the whole day inside a little cave ornament, sometimes she'd chase them, she'd sit there and flare at them.
might work if you introduce them at the same time, but i wouldn't count on it. i know these are different fish then what you listed, i have no experience with rams or keyholes, but since their dwarf cichlids like the kribs i thought i'd add my two cents