Hello, if you are lucky it is just the screen and an LCD/Digi assembly replacement will fix the problem. If you are unlucky it could be a problem on the logic board itself (black-light coil?). The best way to test it is to try a new/used screen.
It is glued on there pretty good. It is possible to remove it and the rest of the frame is identical to the WiFi version. On the other hand it's the sellers responsibility to send you the correct item. Is he going to fully reimburse you if it goes wrong? Probably not, I would exchange it.
Have you tried other adapters? Will it still sync to the computer with the usb cable (if it is dead, you can still try to let it trickle charge from your computer). If no adapters work then check the bottom port for any obvious signs of damage. I usually charge customers roughly $80-$100 to replace the 30 pin dock connector. If it isn't the dock connector then something is probably wrong with the logic board and the price will be fairly high.
I have fixed this a few times before by trying 2 different methods. Swap out camera (which you already tried), or clean the motherboard and connections in the surrounding area with 99% alcohol. For most water damaged phones I take off all of the plates and use a brush dipped in alcohol on the entire surface. After that I let it sit in a container of alcohol for a few minutes.
Hello, there is usually a transparent film on the underside of the back panel. Sometimes it's hard to see but it covers the camera hole, flash hole, and continues down the side. Remove this and see if it helps.