I did 1/2 plywood G1S on the lower 4' of wall. (for a clients house) 1/2" with 16"o/c will be fine. You can use flexable/paintable caulking between the 1/2 drywall and plywood to seal up the seam.
I also glued plywood to the lower conc/fdn kick area. Left a little crack at the bottom so no...
Buy the lift...they are not much. No rush to finish it in one day.
You can do upper walls with the lift also.
1/2 " drywall will be fine for a ceiling. If you have 24"centers you can use "drywall -1/2" ceiling board" It is stiffer for the 24" centers and will not sag between attachment points...