Of course. The serpentine belt must be just tight enough, but not too tight, and it's VERY important to ensure that the belt was put on with the grooves facing the right direction; the groves should line up with those on the pulleys. Make sure that the tensioner has been tightened exactly the way it should be - there may be extra bolts on the opposite side that must be retightened... Each car is different, so check a Chilton's or Haynes manual for your particular make and model.
A stuck or incorrectly installed thermostat.
It can burn you very badly It can cause your heart to beat incorrectly or even not at all
Only if installed incorrectly
If the casing is spilt a filter will leak an incorrectly installed filter will also leak.
Plug wires installed incorrectly. Click the link.
Yes it can. Even if you somehow managed to get it across all tension points if it is installed incorrectly it will come off eventually and something is not going to be turning or operating. There should be a diagram under the hood usually on the panel over the radiator or in your owners manual. Also any auto parts store should be able to show you a diagram.
Yes a loose or badly worn belt will not drive the compressor correctly and then the belt will break
No, backfire is usually caused by park plug wires that are installed incorrectly or an engine that is out of time. Fuel filter and pump will not cause backfire.
Installed incorrectly as in cross threaded. Could also be that the filter was defective.
No, you installing a fuel pump has nothing to do with the fuel gauge
A short somewhere in the wiring, an incorrectly installed bulb, damaged horn ring assembly, etc.
Incorrectly installed brakes that cause the anti-rattle clips to rub. Bent dust shield are the most common, I have seen.