jaguars can be territorial, but some are not very territorial, so it depends with them. a green terror should be fine, but if the tank is 4'x2'x2' then only have 2 fish, but if it has a 6 foot length you could keep something with them, but i wouldn't reccomend a jaguar, try a jd.
my buddy just put a 5inch jag in his tank w/2 8-9inch O's, in one week the O's were no longer alive, 75g tank. i recommend trying jacks, greenterrors, or festea,... depending on the color of your O.
Green Terrors, Red Terrors, Midas, Texas, Flowerhorns, and Jags. when they get older will usually be way too aggressive for Oscars.
Severums are a good match in my experience. JDs too.
Tinfoil barbs would work fine too if you want some non-cichlid tankmates.
I recently had to move some fish around, so I put my 12"+ Black Belt Cichlid in with 2 mated pair 10" oscars in their 6ft long 125 gallon tank. Initially the O's followed the Black Belt around with a little gill flaring. The Black Belt would avoid them (he was the newbie in their established tank). After 2 days the Black Belt turned the tables on the mated Oscar pair and started beating them up. The O's were kept to the upper corner of the tank, afraid for their lives. I had to move the Black Belt. IMO, if I would have put the O's in the Black Belt's tank (his territory), he would have killed them in one night. Oscars are just not that aggressive as far as Cichlids go.
Whatever you try, have a backup plan in case you have to rescue the Oscars. Keep a good eye on them.