it has been suggested that I buy 2 metal studs and glue them to the pole (actually the pole sort fits into them....then screw the drywall into them....?

Just put up the stud walls (up to the post), then overlap the drywall so it meets in the corner. Taping the inside corner should suffice since the drywall will be secure nearby anyway. And since the walls will not be secured to each other, make extra sure they're solidly attached above and below to minimize movement.

You could also just glue 2x4's to the pole with liquid nail.

Is there an adhesive I can use to adhere the top plate to the Ibeam...friction may suffice but I would think that could help...? If I could find a few 4.25 tapcons I could also secure 1 end thru my 1.5" XPS and into the wall.

Liquid nail and shims, if necessary.

I usually rip a corner from a piece of 2x lumber to make a long triangle that is glued to the pole and the drywall can land on.

Outside corners need drywall bead and at least some support to prevent damage the first time they get banged into.