Sweet. Congratulations on the purchase.
The receiver hitch you purchase will depend on what type of WD (weight distribution) hitch you want to use. The WD hitch head is often integrated with its own drop shank.
For a relatively lightweight 22' Bambi Sport (GVWR 4,500lbs, 422lbs tongue weight), I'd take advantage and use a lighter duty WD hitch. I like the Anderson No-Sway WD hitch which I have previously used with a rental 23D Airstream. I really liked it for the ease of use, quiet, clean looking, grease-less, lightweight, and effectiveness for that weight class of trailer.
For lift, I believe the 22FB has #11 Dexter axles. Dexter makes a bolt on kit (k71-724-04), which is effectively a lift block that goes between the airstream chassis and axle. Reasonably easy install. More info here -
Lift Kit on 22' Sport - Airstream Forums
Some other strategies for smaller lift is to upsize the stock tire from a 225/75r15 to 235/75r15 for a small .3" lift (I did this for more tire sidewall for boondocking). Another is to upsize to a 16" wheel with a 225/75r16, for .5" lift. Both strategies often used by Airstreamers.