Still debating if I'm going to pull the compressor... to new at this game to feel comfortable doing it myself.
Silver is good! You'll only probably need to paint the bottom and maybe 1" of the side walls. Read the POR 15 instructions and follow them!!! You get this stuff on your skin and it will be there for weeks. Also follow the storage instructions and it will last for years.
You will need to pull the compressor to paint the bottom of the liner! You'll only probably need to paint the bottom and maybe 1" of the side walls. Easier to rewire, replace fans, T-stat and harness (and I'd spend the bucks to do it while you got it out. Think of all the work you've done just to access the area!
I wouldn't do the masking tape - just POR right over them, just don't allow the stuff to fill the hole (keep a toothpick handy). As I recall, I didn't have any problems with it filling the larger holes. They are usually sheet metals screws, so they don't have much of a thread issue anyway.