Nasty door click when opening is (in order of ease and expense) 1)loose Torx fastener on limiter, 2)broken limiter which you can replace with a good used one or 3) and the most likely culprit, I fear, is limiter strap mount on the body is beginning to tear, and, as has been mentioned, will get worse and more expensive. Welding required. I get about $120 to repair at my indie Volvo shop.

A/C compressor job isn't awful, but will require time and patience. I replace just the clutches at the shop, but it may be easier to replace the whole thing for the DIYer. Essential "trick" to the job is unfastening the engine cradle/subframe at the corner (18mm headed bolt) and maybe the others to gain access. Lower bolts are no problem. Upper bolts also hold the alternator onto accessory bracket. So taking the alternator top bolt loose will help you maneuver. Good luck.