Tropheops chilumba would be the same sorts of colours as dems/yellows so I would go with other fish however there is plenty of room in that tank so you could easily do the dems/yellows/tropheops and other fish.
I would probably start with dems/yellows/cuckoos and build up from there, with a tank that size (and extra volume added by sump you could stick tons of fish in there, best to start with 20+ dems and 10 or so yellows, but there are plenty more options peacocks or haps etc that would be good in there too, I have a few different types and live close to you so feel free to come over and have a look if you want inspiration.