needs the swimming space of a 48" 4ft tank of 40g or more.
Convicts will not attack you, there is no reason anyway really with the correct gravel vacuum to really have your hand/arm in the tank anyway. Convicts are also amongst the most hardy of cichlids, they will do fine in a pH range of 6-8 and a temperature range of 68-82F, if you want to keep a pair, then buy juveniles about 6 and let them pair off naturally, you cannot force them to pair off and they will attack the others once a pair forms, so you need to remove all but the mated pair.
What is your general hardness level (specific number), 7.6-8 if that is the hardness level and not pH is only slightly hard. Without knowing this number then it is hard to offer suggestions. A lot of the cichlids in the size suitable for your tank either require hard water (above 18-30dGH) or soft water (0-3dGH)
All of the Lake Malawi cichlids are out of the equation as the tank is too small for any of them.
For that size tank it would be only 1 Bolivian Ram
and a few dither fish as tank mates.