With Firemouths, Acara's, and Geo's, I wouldn't go with clown loaches. They grow very large and your bottom real estate has already been filled by a bounty of cichlids.
The Silver (Bala) sharks are also quite large, I'd recommend a shoal of something smaller that can fill the upper parts of the tank that the cichlids will avoid anyway, and would be more suitable to the size of the tank. 90 gallons sounds like a big tank, but once you add foot long fish - and multiples of them, it will shrink very quickly.
I'm basing these suggestions on the fact that: a: While cichlids can be crammed into a tank and will accept as small a territory as they are forced too, I don't believe this is the right thing to do for the fish, and B: I'm going with my experience in my 90 gallon US tank, and my newer 110 Gallon US tank - I don't, as of yet, know what the actual dimensions of your tank are.