Can lubricant eye drops stop me from having a blepharoplasty?

Possibly. It depends on how dry your eyes are and whether there are any related changes on your cornea that only an eye doctor with special equipment can observe and document. You may be able to have an upper and/or lower blepharoplasty but check with your eye doctor first. If you proceed your eyes may become more dry (at least temporarily) and you may need to use eye drops more often and/or add eye gel.
No. Blepharoplasty removes excessive skin from either the upper or lower eyelids. Using lubricating eyedrops will not change this issue.
No, but... Tear drops don't affect the eyelid skin. They do reduce eye dryness and may reduce your need to rub the eyes for comfort. Constant rubbing of the eyes can accelerate the stretching of eyelid skin.
No. Eye drops are not for excess skin above the eye, if you have had a visual fields study done and you have vision impairment then we surgically remove the excess skin. Many of my patients do this under local with valium.