I'm assuming your last trailer axle weight was an error
Ultimately, you are:
Within "Towing capacity" for the truck
Within tongue weight limit for the truck
Within GVWR for the truck
Within GCWR (for truck & Trailer)
Within trailer axle rating (per Airstream)
Following mfr recommendations (NO W/D setup)
........so it sounds okay, technically.
Does the owner's manual provide a weight rating for each (front and rear) axle? As long as you are not exceeding a specific rear axle rating....I don't see a problem, technically (am I missing anything else?)
DO check your ball height when hitched...A/S says 18" for your trailer.
Drive it...and see how it feels...