Oklahoma would have to give up Westbrook to get in the Dwight Howard sweepstakes and, if they did, yeah, I think Orlando would give strong consideration to their trade package.
I would expect the Thunder to try and hold onto Harden and Ibaka too while Orlando tries to pry either one of them away in addition to Westbrook. Not sure whether they'd manage to squeeze one of those guys into the trade package or not.
If Oklahoma did offer one of those guys plus Westbrook, I think they'd have the best trade offer out there. If not, it would be a strong offer but wouldn't separate themselves from the pack. It would depend on what direction Orlando's front office wanted to go in.