Sounds like you have your setup well thought out and have a good setup, have you got any pics yet? Might also be a better idea for a mod to move this to the cichlids section..
Dem's and yellows will look awesome together, try to get a few demasoni (recommendation is around 10-12) as they're agro and tend to wipe each other out in smaller numbers..
AS for red or light blue.. For your light blue you could add cobalt blue's or any number of blue peacocks, (fryeri, royal blues, chilumba etc) and for your red its pretty hard to get red africans best you can get is maybe red empress (very hard to get at the moment) or maleri red and even then they're not all red. And also you should only have one species of female peacock in there to avoid hybrids. Maybe go for something common like red zeb's they're more orange though, or if you want a different tank you could stick some red rainbows in there..