Feeding I is a subject you might have some of the Troph pros answer.. They are prone to bloat like Oscars are HITH. Form what I've seen in others tanks. I had some for a minute.. Never had a problem..
And allot of the locals here... Keep them in colonies.. I had them with several species..
I only noticed species specific aggression.. and it wasn;t much.. But I ONLY had three I would wait and see what the OldWorld keepers say.. They should be around later
The bigger the group the less agression you get 12 sounds fine, my uncle had a 5x2x2 with a group of frontosa and tropheus and both species were breeding.
I would say that it could be done provided you fed them NLS. I know quite a few people who feed NLS to their trophs &/or Fronts. Can be a good mix for both, but I'm not sure that you would want to keep them on such a non-varied diet. It could go either way.
i have tropheus mixed in with my mbuna, they are doing great. The get Hikari and NLS. Had them bothfor 6 months plus, no bloat and no aggession towards other but they do fight between each other.