You definitely don't need a body lift for only 265/75R16 tires. I've been driving hard on 285/75R16 for 6 years without a body lift, although they rub in some situations. Minor rubbing doesn't hurt anything. Even if you had larger tires, a 1" body lift won't resolve the primary rubbing problems, since the body has to move up a few inches to really get rid of the rubbing problem at the rear of the front wheel wells. Just get a hammer and pound the body seam in a few places, which will avoid rubbing enough to avoid needing to mess with a body lift, even for 285/75R16.

Body lifts can be very good if you are determined to fit huge tires or do a SAS, or other extremes. If you want to do a body lift, you should decide before you add custom bumpers and rock sliders since it will affect how all of those are mounted and whether you need to customize those.

A suspension spacer used in combination with other lift springs in the front will affect the ride quality because it will change the geometry of the IFS. It will seem as though it's stiffer. Exactly how much I don't know, since I haven't tried that. I have a spacer above my rear OME springs, but it doesn't really matter there since it just holds the entire rear axle further from the body/frame.