I have done this before and I found out that you can swap the displays and it will work, but with some issues. (i´m not sure exactly of the parts number i used, but in my experience) What I encountered so far, is that: - When turning on the MacBook the Apple logo and loading bar screen will show after a couple of seconds. - Sometimes the backlight will lock up and will not increase/decrease, this can easily be fixed by “sleeping your screen”, then turning it back on, i set that the lower left corner of the desktop will sleep my screen, so whenever i have this issue i just roll the cursor to that corner. iSight camera, bluetooth and WiFi works perfectly.
It sounds like a faulty Audio IC chip and this can be fixed by the jumper wire - reball method. If it fails, then you would have to replace the Audio IC. A somewhat difficult task if you are not familiar with this type of repair level. I have fixed 5 phones with this exact same issue, already fixed.
On my experience this is what you can do: 1. Restore to factory setting via iTunes. if still fail then, 2. If you can test another proximity sensor. if still fail then, 3. You will have the next issue. - Faulty soldering on the Audio IC chip and this can be fixed by the jumper wire - reball method. A somewhat difficult task if you are not familiar with this type of repair level. I have fixed 5 phones with this exact same issue, already fixed.
You can re-glue it easily. Just clean everything before placing adhesive. I been using B-7000 for this task and works like a charm. Just use a very small drop on the edges, careful not getting glue on the middle of the lens or the camera.
Use the iPad 3/4 touchscreen, just fold the flex cable and tuck it under the LCD, make sure you don't tear it or rip it. it will work. I been doing this for years. The camera bracket is different, just swap it for the broken one.