You could go with the more rare versions of Oscar like wild, Lemon, Chill Red, longfin, or veiltail to have a special one.
And the Oscar shouldn't bother a catfish so long as it's won't fit in the O's mouth. My Oscar lives with a p. Ornatus. (Bigger cousin of Pictus cats, gets about 12in)
I can appreciate what people have to do to breed Flowerhorns. But them giant hump heads just don't look right. Seems like the fish would flip over due to it...but there are a couple I do like. They don't seem to get the giant humps, but normal ones like most male cichlids do. So I would take a look at Red Texas, and Golden Phoenix that Arizona Aquatic Gardens carries. Both beautiful and look like real colorful non hybrids.
Just an idea. I was considering getting one of each and see what kind of fry they would make.