Can anyone send mail to a recruit

Yes, but the sender has to address it directly to the recruit with the correct name, ship # & division #. Also, make sure its just letters.... No food. No glitter. No confetti or anything loose that could get their ship messy and the Recruit in trouble.

Yes, address as stated already needs to be exact. Mail only, anything else will get the recruit in trouble.

Sure. You just need an address

It depends on what you mean by anyone...

Yes. Make sure the address is exactly correct.

Yes they can, you just have to know exactly what the address is and how to to address it. (Ship # and division #).