It can be replaced, but it isn’t easy. The camera housing is spot welded into the metal part of the housing so you have to cut it out of the frame. Attaching the new housing also has to be done with some kind of super glue so it binds tightly to the metal. Hope this helps!
Take a look at the wifi antenna near the top of the logic board. Any issues with this antenna will greatly reduce iPhone’s ability to detect and connect to wifi networks. Hope this helps!
It sounds like your phone is in DFU mode. To take it out of DFU mode simply hold the power and home button down together until you see the Apple logo, then release both. If your phone reboots successfully then you should be able to make a backup of your phone and save your data Hope this helps!
It sounds like the board may have been damaged due to the drop. I would try opening the phone and looking for anything that doesn’t look right, cables amiss, stuff like that. If nothing looks wrong it could be board damage. Hope this helps!
Aftermarket batteries will often do this, even occasionally causing the screen to flicker around the edges (especially when the phone is low on battery). If it doesn’t get any worse I would say it’s just due to the battery and shouldn’t really be any cause for concern. Hope this helps!
It sounds like it could be the LCD starting to fail. I would try testing the phone with a known good screen and seeing if that solves it. Hope this helps!
Make sure that the holes at the bottom of the phone are free from debris, as it can often prevent the mic from picking up audio properly. Hope this helps!
I’ve seen this happen a few times. Go to Settings > Mail > Accounts > *comcast account* and you should see a button that says “Re-enter your password”. Click this button and enter your password and it should start to work again. Sometimes the prompts to enter the password from the home screen don’t always work so it is best if the password is entered directly into settings as I described above. Hope this helps!