Keep your eyes peeled for breeding agression down the line.
I've successfully kept breeding angels with breeding dwarf cichlids, but I had a tank that was planted to within an inch of its life including a 10" deep, 24" high wall of vallisneria along the whole back where stressed fish could hide from each other.
If it is going to work long-term when fish start pairing up (most likely the discus since you want more of those), you will definitely want a good tall and thick plant wall to let fish escape from a spawning pair.