looks like your screen lamination is not holding up. (the glue that holds the digitizer and lcd together). Im not too sure you could easily fix this without separating the digitizer and lcd and applying new adhesive which is pretty hard to do without breaking your lcd due to how fragile it is
From your picture I'd guess it's a connector bracket of some kind. I'd be careful to not knock the around as it could possibly disconnect that connector. As far as functionality goes, you should be fine
Have you tried reconnecting the connectors from the screen to the logic board? If you have, I'd make sure that the pins on the motherboard side of the connector are all intact and if the pins on the speaker are making contact with the front camera/speaker/sensor assembly.
The only thing I can think of is to check the fpc connector on your motherboard and see if it is intact, it is possible that the dro could have dislodged a pin and that may be causing your problem. Sadly if this is the case, you'll have to get a new fpc connector soldered on by a professional.
Yeah most likely. Try reconnecting the lcd ribbon and also making making sure that the connector pins are intact. If that doesn’t fix it then probably you need a new one. I had this problem with my iPad mini 2 as well and i ended up replacing my lcd.
The power and volume button assembly is soldered to the main logic board, so unless you have micro soldering skills, this repair is out of the average person's ability to repair. There might be services that do the repair but I'm not sure.
The best way to test it is to make sure auto brightness is on, then when the brightness is all the way up, put the phone into sleep, put your finger over the sensor an wake up the phone. If it works, the screen should dim and get brighter when you remove your finger. (Do this in a bright room)