First, firemouths are not african cichlids, and jewels are from the rivers, not the lakes in Africa (africans from the lakes will slaughter them). For compatible fish, go to cichlid-forum.com and look at their profiles section (stick with fish from lake malawi). They have information about almost every cichlid known to man. Realistically though, Demasoni are not a 'community' african. They don't always play nice with others.
Second, a 10g tank is not suitable for any African cichlids other than shell dwellers from Lake Tanganyika... and to grow out fry.