Bro, put this in the threads for your tanks, forum etiquette to not derail someone else's thread with an unrelated question. I know your new here and its fine, but just letting you know so you learn.
To the OP- I would stick with south American cichlids. Oscar is SA. Jack Dempsey, salvini, texas, are CA. Which are generally much less tolerant of other cichlids. South American cichlids live with many other cichlids in close proximity in the wild, so they tend to kill each other less in aquaria.
Some examples of SA cichlids that would work- Severum, Satanoperca jurupari, Geophagus Tapajos redhead, guianacara gaeyi, B. Cupido,
If you really want the jack Dempsey and your pH isn't low, I would say give it a shot. It might not work out, but JD is one of the milder CA cichlids, and I have found them to be great tankmates for Oscars. The problem you might run into, would be trying to mix the JD with the smaller SA's like cupido. Personally I would scratch the JD and go with the SA fish, but if you really couldn't live without the JD, it might be fine.