Now, you didn't mention sand.... you'll have to alter how you vacuum your substrate (yes, that is the right word...), just grazing the surface to pick up the gunk on the top, without digging in and sucking all of your sand out....
I would be more worried about your africans beating up your cons than the other way around. I had 3 mixed dwarf africans in a 55 gallon with some much larger fish, including a 9" pleco, and the africans beat the pleco to death over territory.... they also did a number on some of the other, much larger cichlids in the tank. They have strength in numbers, I think.
Hmmmm... for a 28 gallon, I wouldn't do more than the pair of cons OR a pair or two of D.A.'s, otherwise, they will kill each other over territory. Otherwise, a few tough bottom-feeders (cory cats, for example, tend to tolerate almost any tankmate that can't outright swallow them... a raphael might be another good choice, they're too spiny to be chewed on, and they grow pretty slowly...) would complete the setup nicely. Don't go overboard, though, as cichlids need their space or they get really mean....
I would be more worried about your africans beating up your cons than the other way around. I had 3 mixed dwarf africans in a 55 gallon with some much larger fish, including a 9" pleco, and the africans beat the pleco to death over territory.... they also did a number on some of the other, much larger cichlids in the tank. They have strength in numbers, I think.
Hmmmm... for a 28 gallon, I wouldn't do more than the pair of cons OR a pair or two of D.A.'s, otherwise, they will kill each other over territory. Otherwise, a few tough bottom-feeders (cory cats, for example, tend to tolerate almost any tankmate that can't outright swallow them... a raphael might be another good choice, they're too spiny to be chewed on, and they grow pretty slowly...) would complete the setup nicely. Don't go overboard, though, as cichlids need their space or they get really mean....