Good questions... I wish I had answers to all of it.
Who knows if the water temp was actually touching water at that point as the water had squirted out by then. Typically, in 10 minutes it would get up to 185F. I honestly don't know if it has a thermostat. I'd have to check.
Water/coolant was coolant was leaking from the top of the water pump where the intake hose and would be heater hose would connect. My guess is the plug on the outlet of the heater hose was cracked and caused it to burst.
I don't know what was making the metallic noise. Water pump bearing? Rocker Arm assembly? Your guess is as good as mine. I just panicked to shut the car off.
Sorry, I'm just very frustrated/overwhelmed at the moment.