2010 Range Rover HSE Speaker Issues and Tweeter Replacement

About a week ago I experienced crackle noises and hissing from the front passenger, right side speakers (Tweeter and mid-range). Oddly, I hadn't been blasting music, but this occurred right after I turned the car on. I was hoping that it might be a wiring issue, but sure enough, it seems that the speakers are blown. My Range is a 2010 HSE black on black, with about 92,000 miles.

I took the vehicle to my local land rover dealer, and 200 bucks later they "diagnosed" the issue and said I needed a new amplifier ($2200) and new passenger door panel ($1800) because the midrange speaker is not removable. Land Rover said my amplifier was pushing 14 volts to the damaged speaker on the passenger side and 9 volts to the undamaged speaker on the driver side.

I then took my rover to a car audio shop, and they said that the amplifier is fine (they explained that the damaged speaker was accumulating the extra power and thus the higher voltage and usually an amplifer failure means all speakers stop working), and that the speaker mid range was blown. So they disconnected it for now, but they confirmed that I would need a whole door panel to get that mid-range speaker back.

With that in mind, I'd love some tips:

1) My tweeter is hissing. What's the best method to disconnect the passenger tweeter to at least stop the hissing while I wait for new parts to come in? Also, any instructions for replacing the tweeter would be great. I can't seem to find this procedure in the service manual.

2) Are there any workarounds to replacing the mid-range speaker without replacing the whole door panel? I realize that from the looks of things, it looks darn near impossible? Otherwise I think my best bet is to buy a used door panel for about $450 on ebay.

3) Any chance my amplifier is indeed malfunctioning? I did witness the car audio shop plug in an external speaker to the same hookup as my damaged mid-range speaker and it was playing fine. I just want to avoid installing a new door panel speaker and having it blow out again.

Many thanks in advance! Other than this speaker issue, my Range puts a smile on my face whenever I jump in : )