I see people on here messing with far worse....
In my opinion, if the rust isn't horrible, the most important thing is interior plastics, if you're going to leav an interior in it. Wagon plastics are especially hard to find these days, and unlikely to ever be repro'd.
Remember, if it needs front doors, Malibu and the Pontiac 4-door versions are the same. Rears are wagon-only as an assembly...they're the same from the window down..so if a guy needed one really badly you could try swapping the window frame section to a sedan rear door.