Welcome.

My opinion. The roll down rear window is clutch. if they can put it in an ambulance door then fine but don't get rid of it just so you can mount a tire to the hatch door when you can put it on any rear bumper.
Didn't the old GXs have a rear door spare option? I thought I had seen that before.
FWIW I have a 33 in the stock tire space. the downside is that it does worsen your departure angle.
I don't see how the KDSS is an issue. It's not a required feature. Just buy without it if you do more aggressive off-roading. You probably don't need it anyway when you have the higher end suspensions like King and your BP-51s.