No ... you must show proof of US residency, and pay taxes like the rest of us, hence the need for a SSN.
No. You have to have a valid Social Security number, which the military will check to ensure is yours.
You can not use a Canadian SSN to work in the US
As of 2011, gay people can freely join the US military and do not have to hide their orientation.
Yes
No, you cannot.
Height doesnt matter in the US
Sir Yes, Sir!!
Not in the US military, no.
U.S army
Yes. You can join the US military without being a citizen, so long as you've established permanent residence and have declared an intent to obtain citizenship.
You don't. You need to be in the US.
One can join the US military as young as seventeen (17) with parental consent
The Coast Guard is a branch of the US Military, so yes.