PA/Fed law on legal aliens owning firearms

[Hawk]

For you FFL guys and PA Gun Law experts.

What are the requirements for a legal alien on a work Visa living in PA to purchase or possess a rifle/ammo (AR15) in PA?

From what I gather:

1. An alien legally in the U.S. may acquire firearms if he has a State of residence. An alien has a State of residence only if he is residing in that State and has resided in a State continuously for at least 90 days prior to the purchase.
An alien acquiring firearms from a licensee is required to prove both his identity, by presenting a government-issued photo identification, and his residency with substantiating documentation showing that he has resided in the State continuously for the 90-day period prior to the purchase.

Can he purchase a rifle from a private individual, instead?

2. Has to take a Hunter Safety Course and obtain/maintain a PA hunting License.

3. It's also my understanding that without the above, he can't even posses or "shoot" any guns or purchase/posses any ammo.