I have a 180 gallon with one oscar, 2 giant pacus, 1 green severum, 2 pearl cichlids, 1 convict and 1 blue acara. It's a great community tank so far. The oscar chased the convict at first a little...but now they get along pretty well. I think the space helps.
I have my 2 Oscars in a 180gallon with 8 silver dollars 2 convicts and a jade eye but i have a much larger tankj than you so i'd suggest you get out and get a larger tank for your Oscar then consider tankmates.