Okay, I've looked at all the fish you've considered, and will be doing some research for suitable substitutes,
This could take a few days, so please be patient
tiger barb
clown loach
Geophagus
shark(minnow)
Pleco (no larger than 4 inches when grown)
Cory catfish
tiger barbs
cory catfish
blue gourami
angels
4 gold barbs
4 panda cory
2 Bolivian Ram (has a wider range or water parameters than the German Blue Ram)"
I will say that Rams are probably the best geophagus substiute, even the scientific name fits,
mikroGEOPHAGUS