Keep in mind that these fancy plecos need to be fed more carnivorous foods, which may at first sound like they would make perfect additions to your oscar.
I have a cactus, and let me tell you it is difficult to mix with cichlids. They are usually more shy than gibbiceps, so by the time they actually move to go eat when you feed them, the food is gone.
I threw mine in my 230 gallon, with a bunch of cichlids. Gibbiceps was in there with him. By the time he would come out to get food, there would be none left. Gibbiceps ate fine though. Now he is sharing a 90 gallon, and I always watch for him to start eating before I leave.
Most of the larger growing fancy plecos would be fine with your oscar (though sometimes oscars are tempermental and will keep attacking relentlessly), but getting enough food may be a problem.