I presume you meant "110 or 220"? If so, it's definitely 110V (a.k.a. 120V) with a "normal" 3-prong wall plug (NEMA 5-15). Wattage is 550W, so no risk of popping a fuse or breaker.
Like an electric stove element on high (it glows red).
I wouldn't let this thing touch the actual grilles (grates), and there's no reason that I can think of to do so.
You just stick the loop in your pile of charcoal and plug it in. Watch out! It gets as hot as an electric stove element on "HIGH".
It operates on normal household 120V power @ 550W (so, around 4.5 amps).
The starter only lights the fuel it's actually touching, which in turn lights the fuel around that. Even when using chemical starters, you should only be trying to light the "heart" of the fuel pile, in furtherance of the aforementioned chain reaction.
We can divide the given wattage (550W) by the voltage (120V) to get the current in amps (~4.6A).
No, this device is not waterproof.
No wouldn't hang it on the inside; could set the door on fire. I hope this is a joke.
Absolutely not, it is not intended for such use and will be dangerous to use in that manner. Mike