The fish will dig
And I will say thats not a mix i would recomend to someone it's usually best to keep the mbuna and haps seperate though yours are the of the agresive utaka types, my nimbochromis venustus died in my mbuna tank and maylandia lombardoi kennyi are very agresive, in a large tank it should work at least 125 but i dunno
EDITED- Nimbochromis venustus need at least 100 gallons or 125 gallons I think you have a 77
anyways it does look great