IMO you don't need more than a pair of severums and even that can be pushing it. Severums may not grow as large as an oscar, but the males do get pretty large and thick. My super red is about 10" and my Atabapo pair is larger than that.
You said in your oscar sale thread that you didn't have time to take care of it anymore, so what makes these fish any different? If you don't have time to take care of your fish, I certainly wouldn't recommend other large SA cichlids like severums, or sensitive fish like rams. Just my opinion.