Beautiful fish! Nice to see how they're colouring up as I read through the thread!
I only know a little about rams, although I do plan to have some rams and apistos at some point in the near future.
My concern with your tanks right now though is size/overcrowding I'm afraid... Not having a go at you, just asking what your plan is, and concerned that these delicate fish won't handle extra stress too well.
A 15g tall has a very small footprint, and two out of four corners are now taken by four fish. I'd be concerned that the pairs are going to be stressed out, when they're having to constantly defend against so many other fish always in their territory. The unpaired fish might become stressed from being chased all the time and not having anywhere else to go!
You said you were planning to keep one or two pairs yourself, but where do you plan to put them? From what I've read, a 15g tall isn't enough footprint space for one pair, let alone two. Your other tanks listed in your profile are also small, but with fish that will need much more space once they're larger. Are you planning to upgrade tank sizes?