See my answers below:
1. The maximum processor temperature is 105C; the processor will shut down to prevent damage.
3. If the BIOS throttle set point is different in BIOS then it will throttle at 90C. This is possible only if the BIOS has options to change this settings.
4 and 5. 58C for the processor playing games is an actual safe temperature. The processor has been designed to work at high temperatures