Severum/Rainbow Cichlid With Angels

Hi John(?), welcome to the forum.
A severum would be too much for Angels, much bigger, more powerful, and they would spend most of their time keeping out of its way and being stressed. A Rainbow might be ok, but ideally it needs hard water...

Hi there, and welcome to the forum. 

Conflicting information regarding fish is quite a problem, and for every story of fish species that don't get on you'll find someone with experience of those species sharing a tank without incident. Fish have individual personalities, as well as species characteristics, so mixing fish is always something to monitor.

It may be quite difficult to find fish that are large enough to cope with what you already have, and laid back enough not to bother them.

It may be worth a trip to your local store to have a look at what they have, and look at the Acaras and Flag Cichlids, to see if you have any preference. If you see anything else you like you can always fully research the compatibility when you get home.

I don't have any experience with angelfish, so can't advise further, but please keep us updated on this and let us know if you find any other fish that may be suitable.