Sounds like the LCD is malfunctioning. Could be a bad part or a loose connector inside device when dropped. You can try an old repair trick....hold the device about 12" from a solid surface and drop it (display up) with the display on. This often works on iPads that have LCD issues.
Sounds like a keyboard shortcut issue. Try checking your keyboard shortcut assignments to make sure "Show Desktop" is not assigned to the RIGHT CLICK function of mouse. Reassign key shortcut, test, and put back to F11. EC
Check the Apple Part # on the ribbon of the camera. iPhone 6 camera - Apple part # 821-2460-03 iPhone 6 Plus camera - Apple Part # 821-2208-04 iPhone 6S camera - Apple Part # 821-00027-03 Unfortunately, they are all slightly different specs and are not compatible with different models.
Locate a donor keyboard off Ebay and pop off the broken key to change with new key & butterfly hinge. You will want to verify the key action still works before doing this....i.e. on-screen keyboard recognizes the right-shift keystroke. If it does not recognize the keystroke then you will need an entire keyboard assembly.
sounds like an antenna issue like those above have indicated. Have you tried to RESET NETWORK SETTINGS in the general menu? Put you phone in Airplane Mode and try this. Besides this the only approach left is to try and restore the iOS. You might also verify your SIM card is seated properly and the tray is flush with the frame. This would also cause your symptoms.