Mark, congratulations on your newly ordered Airstream!
The factory does not offer 16” wheels or a lift kit as a production line option. Both can be dealer installed but you’ll have two sets of wheels & tires (unless the dealer will work with you). There’s nothing wrong with the 15” wheels and Goodyear Endurance tires.
Unless you’ve got a need for the lift like a heavily sloped driveway, try it for a while and see if you really need it.
Check out the forum thread
“What did you get for your trailer today?” for ideas of what you might want to modify once you get the unit. I’d start with a good TPS system (we have TST). Lots of tips and tricks here on the forum!