I would say no you really shouldn't mix in new world and old world cichlids. Eventually the Africans or the cons will kill each other it's only a matter of time. Plus they have different diet requirements the Africans nedd more a more veggie based diet, while the convict requires more meat.
I think there is enough room but I agree about the diet. My biggest fear was the convict eating the Africans. But before having the two was fine. Now I'm hoping with this much fish they won't be able to set territories.
I only keeled Africans about a year. South and central about 5 years. So I forget how they can be. I figured start them all small and adding the all at the same time would be a good thing
That's true but those diet requirements are really going to cause issues. I would rehome the con if I was you. I would simply because your con needs meat in his diet. If the Africans eat to much they will most likely become bloated and die. Then if the con doesn't get meat because feeding them non meat baed foods he will become disease ridden and die from lack of nutrients.