Yes you can, but be aware that usually Oscars are pushovers, all show not a whole lot to back it up. My green sunfish that was 3" smaller than my oscar he was was bullying shows this. The Peacock bass I believe would hold its own.
yes it's fine, just make sure that the temps are regulated to no less than 75 and all should be cool.
Try it and let us know. I've mixed natives and cichlid in the past with, well "mixed" results. I personally would avoid the oscar/LMB combo as oscars tend to take a beating in my own experience. Mbuna and sunfish worked well for me at least.
The oscar I have now is 15"-16" and is in a 280 with one pleco. His owns the 280 and thinking of trying him with my native crew. He likes being the only fish though but I would really like to do something in my 280 besides one oscar.
My oscar has been in with my native crew for almost a week now and doing great. Wish I would have done this along time ago. Moved my Texas Rio into my 280g and hopefully he will gain some size so I can put him in with the others. Now Im looking for a pellet trained Mono Peacock Bass.