I keep my Ikolas with REd Throat Lupota for about a year, and have not had one incident.
However...not only in this forum, but with personal friends, and in books I've read, nearly ever hybrid case I have come across has envolved sp.red crossing with sp.black, or other moorii.
I think you can put them together, but you have to understand that you will have to watch them very closely as I do with my Ikolas and Lupotas. If there is any sign that they might be courting one another, you have got to immediately seperate the groups and cull any fry in the tank until you know for certain they fry is 100% pure one variant.
If you do not have the time to dedicate to watching them that closely, I would not risk it. I would keep the groups seperated.
The only Tropheus I know for certain that is 100% safe to mix with other Tropheus is Duboisi. The rule only applies if you do not mix two differnet Duboisi types in the same tank.
Unless the juveniles are wild caught coming in as juvenile size I wouldn't add to it. If you add juveniles that are not wild caught to your wild caught colony you cannot sell the fry as being F1 once those juveniles are full grown. Because there is no way for you to tell if the wilds bred with wilds or the wilds bred with the juveniles.
So if you intend to sell the fry then I wouldn't add to the colony.
I can get ikola, bemba, duboisi, moorii "moba", and moorii "chiwa". I have ikolas and moliro reds already. Just wanted to get more ikolas or others I can mix with either group. Fish will come in at 1.5" if I decide to get any.