Catfish will eventually see them as food prob. cuse it will outgrow them quicker. Datnoid should be ok for awhile. I really wouldnt suggest keeping them in a tank with fish that get bigger then them or that can fit the fronts in their mouths. The pH may play a problem may not. I keep my fronts, which maintain nice colors at a 7.5-8.0 pH and they do great. IMO I think pH can vary with all fish to what they tolerate and do best in esp b/c they are tank raised.
Frontosa aren't stupid fish, they just freak out when you startle them. You would need an aquarium that's at least 6 feet long (125 gallon).