Yes, they are legal under State law. Idaho state law does not prohibit ownership of fully automatic firearms by private citizens. However, Federal law requires that any fully automatic firearm have been registered with the Bureau of Alcohol, Tobacco, Firearms and Explosives.
Yes
Idaho does not prohibit possession of either a semi-automatic rifle, nor a fully automatic rifle (machine gun) Fully automatic firearms are regulated under Federal law in ALL states. Possession of a fully automatic firearm is legal in Idaho so long as the gun has been registered with the Federal BATFE.
Yes
Yes
Yes- if registered with the BATFE and with the State Police.
In America, yes. You must have the proper paperwork and taxes paid.
Yes, with proper licensing and NFA tax stamps.
Provided you follow all the appropriate laws, yes.
Provided you comply with all the federal, state and county laws, yes.
Yes, provided the firearm itself is legally obtained.
Yes, the M16 is an assault rifle, and thus has fully automatic capabilities. The XM16E1, M16A1, and M16A3 can fire on completely full auto, while the M16A2 and M16A3 can fire a three-round burst, which by legal definitions, is considered to be fully automatic.
Because its fully automatic, and was not importable pre 1986 (when the assault weapons ban was introduced). Only fully automatic weapons produced pre 1986 and were already legally owned in the US are now legal in the US. Although it IS legal for Police Departments to own Glock 18's, if they have been trained by Glock. It is also legal to own (in certain states, with strict stipulations), a Glock 17 (or any other model besides the 18) with a fully automatic sear. Which is essentially a Glock 18. **I Am NOT A Lawyer***