I think DPS is in Asia. (Is Jakarta in Asia? Yes, so one presumes all of Indonesia is by reference.) Thus yes, too many Asia segments.

AA 855 is a through flight from BWI to LAS. Not sure about seasonality.

If you're in N. America, I'd recommend getting the itinerary koshered by the BA RTW desk here (IMO about all they're good for) then get the PNR and send THAT in the fax to IST. Once they can pull it up on the system, ticketing goes much more smoothly.