I think it's Swissport but Squeezy has their own dedicated check-in area. One queue for all their flights be they U2 or DZ. Not like smaller airports where you check-in/drop by flight.
My tentative plan has me back to GVA around 1740 for a 1850 flight. Not enough time to drop bag and go through security.
I really would like to avoid taking 2 large bags (only half of one is my stuff) and a carry-on on the bus/train. But, for the moment, that will be plan B.
Taxi to the airport will be more than the flight cost.