I kept them before, in my experience they get along with anything that doesn't look like another creni. Silver dollars, angelfish, datnoides, various cichlids, stingrays... all not a problem. Even fish they could easily eat they ignored.
However, if they don't like another fish, they are ruthless beasts punching way above their weightclass.
The one fish I kept they did kill was a silver arowana, they bit his fins and did the alligator role. My theory always was that due to the somewhat similiar size, colours and patterns, they thought he was another creni, as I can't really think of another explanation.
Your bichir have a similiar shape, so I don't know how they will react to them. The rest should be fine, tho they will put your Oscar in his place if he tries anything.
