Remington 30-06rifles are legal anywhere in the US that all other rifles are legal.
"Legal" denotes a law- and the law varies depending on where you are- and you did not tell us that. In most of the US, firearm suppressors ARE legal, but must be registered with the Federal BATFE, and a $200 transfer tax paid. Please note that for most rifles, a suppressor does NOT "silence" the rifle, but can greatly reduce the sound.
There are two answers to that term. CARBINE is the general term for a short rifle. However, there is a LEGAL term in the US- Short Barreled Rifle. This refers to a rifle whose barrel is less than 16 inches long, and/or overall length less than 26 inches. Under the US National firearms Act, such rifles are legal only if registered with the BATFE, and a tax paid on their transfer. They are in a similar legal class with sawed off shotguns and machineguns.
Depends on the air rifle. England restricts certain higher powered air guns that have enough energy to be useable as a weapon.
Firearms that are imported into the US must go through a legal process- and it is much more complicated than simply dropping the rifle in the mail. As your question is phrased, my answer would have to be probably not. Sorry-
Technically its owned by your parent (or legal guardian) that gave it to you if your under 18. If your under 18 for a rifle or 21 for a handgun you can't purchase one.
Yes, it is legal. Florida has no AWB in effect. However, anything you add must be US made.
18
Depends on where you are.
The minimum legal barrel length for a rifle without requiring it to be tax stamped and registered as a Short Barreled Rifle is 16 inches - that's federal law, and not just Vermont.
Well, that depends on the laws where you live. In most of the US, they're perfectly legal, with the one exception being California. In other countries, the laws are much different.
You must be 18 to buy a rifle. The stock has nothing to do with it.