aro, 3-4 P-Bass and a ray sounds like a good set up to me. Because of your tank size i'd try and find one of the smaller species of Ray (talk to the Ray guys about that though, i've never had one) and a black aro as they're much more placid then Silvers, Don't suffer Drop Eye, and don't get as large. Much better looking too!
Depends upon the temperament of the Jag if it destroys tank mates - mine doesn't. If you go with what you had planned for now then later on you might come accross another fish you really like the look of and will go nicely with what you already have. Get that rather than buying one mentioned on here that you might not really like in the end (talking from experience here!)
