There are 11 different licenses. One- the 03 C&R FFL license, is for collectors- you must be 21, and not prohibited from owning guns. All others are business licenses- you must meet those requirements and be licensed to engage in the business covered under that license.
Federal Firearms License
No. Aside from the federal law which states that a felon may not have access to, be in possession of, or purchase firearms, anyone who handles firearms in that shop must be covered under the shop's Federal Firearms Licence - any employees who are included under that licence may not handle firearms in that shop. No convicted felon is going to be approved for that.
Illegal to do without first possessing a Type 7 Federal Firearms Licence.
Technically, states are the entity administering the requirements surrounding the issuance and rulings/laws relating to firearms. The Second Amendment is a Federal constitutional instrument.
No. A Federal Firearms License is a licence to engage in the business of selling guns, or to collect guns, or make guns, or import guns, or make ammunition, etc. It has no bearing on CARRYING a gun, which is regulated by STATE law. There is no FEDERAL law on carrying of firearms, except certain Federal property prohibits carry, and that a law enforcement officer may carry in any state. If someone tells you that have a Federal Concealed Carry permit, they are lying.
Maybe. Problem will be if spouse has been adudged mentally incompetent, they may not have possession of a firearm. That includes access to firearms. You can discuss the particulars of your circumstances with the BATF firearms technical division for a more specific answer.
Yes. In fact, as a naturalised citizen, I own several, and hold a Federal Firearms Licence. You can actually buy one without being a citizen, as a matter of fact.
At least 21
A Type 7 or Type 10 Federal Firearms Licence, with a Class 2 Special Occupational Tax Stamp. You need to obtain that before you even think about doing this.
You would need to specify what "firearms licence" you had in mind, as well as the location you were referring to. In most of the US, no such licence is needed, save for Illinois, which requires you to have a Firearm Owners Identification Card (FOID).
A firearms dealer. To be able to do business as such, you must have a Federal Firearms Licence (FFL). Most gun shops will have a Type 1 FFL, and pawn shops will have a Type 2 FFL. A Type 3 FFL is the only class of FFL which does not permit the possessor to act as a dealer.
No. Silencers are against federal law, so no state law can over ride it. ------ Actually, that is incorrect. Suppressors (silencers) are quite legal in the US. Federal law restricts them, but does not prohibit them. The federal requirements are not difficult to meet. Checking PA state law it appears that suppressors are also quite legal in that state so long as you comply with the federal requirements.