Personally I wouls go with a slightly larger tank. more water tends to be more stable. 10 gal(40l) tanks are subject to sudden spikes.
shoot for a 15 or 20. if you want dwarf cichlids go for a 20 long as mant of the dwarves utilize the bottom half of the tank(tho mu bolivians will swim to the top to feed.
also..not all cichlids are aggressive..as a matter of fact many of the smaller cichlids need to have dither fish to feel comfortable.. Keyholes for instance are very timid(for the most part) you would be well advised to get some dither fish with them to allow them to feel more comfortable..Cardinal tetras work well with keyholes.'
also the Altispinosa (Bolivian/butterfly ) rams are fairly peaceful and do well in smaller aquarium environments. that are also Hardier than the blue ram.
consider the appistogramma also.
also check the cichlid forum for more advice.