The only license you need is your drivers license (or handgun license if you live in a state that requires one) but those are used at the FFL that you choose and not on Buds. Now NFA items are awesome but in a different section and require a lot more paperwork and such (but you would definitely know if it was that type of item; which the item you chose is not). Awesome model!

No. It's a semi-automatic pistol. If it were an SBR (short barreled rifle) or fully-automatic then it would require a tax stamp. As long as you do not add a stock to the rear or a vertical grip to the front you are fine. That said, it is always good to check your state and local laws for other restrictions (e.g. FOID).

None as long as it good in your state your good to go

No special license required. It is considered a pistol.