No.
no if he has a permit
The SKS is not an assault rifle, nor even a BATFE-defined "civilian assault weapon". And no, a permit is not required.
Yes, once you've obtained an NFA permit for it.
No
No.
Without requiring an NFA permit, the largest bore weapon a civilian can own is .50 calibre/12.7 millimetre in the US. Anything with a larger bore requires an NFA Destructive Device permit.
In MOST of the US, a permit is NOT required to purchase a .22 rifle. IF one is required in your area, it is because elected politicians passed a law that says you need a permit. You would need to ask them why they did that.
Yes
No. Minnesota requires a transfer permit for handguns.
Depends on the laws where you are.
Get an NFA Class II permit for one.
yes