Real shit

I’ve had good success tapping stripped the screws loose with sometring sharp and a hammer

Not sure if you can get something small and strong enough, small punch or sacrificial screwdriver might work

Here is a video of what i mean

https://youtu.be/SXNAW96O_d8?si=cxJt59PKdEOQDuqV

Case usually have fans preinstalled that should be fine. Just pay attention to the direction, have tham all blow air front to back. There is usually an arrow indicating which way it moves air.

Run a benchmark after buiding the PC and check temperatures.

Not with that attitude.