barracudauk i currently have 2 silver dollars with my remaining wolf fish the female died, the silver dollars have been in there before i got the wolf fish however i did have one episode where the female had one of the silver dollars in its mouth had to get in there with a net to save it!!
I used to have two 13" knife fish with my wolves they got beaten up quite badly, i had to get rid of them before they got killed.
i think you may be able to keep other fish as long the wolves are brought fairly young, with mature wolves you may struggle especially with fish that are seen as food competition or a threat, i think wolf fish can over power and kill most fish including piranha, large cichlids and snake heads.
its always a risk mixing any fish with wolves its trial and error mate sorry cant be anymore help
kane