In the US, you do not. Additional laws regulating flare pistols and other launcher types may exist in your home state, and should always be checked first.
Do it through FFL's in each state.
You either need to have a current federal firearms license or have the gun you ordered shipped to a FFL dealer. Most FFL dealers charge a moderate fee for this service.
No
You can sell your privately owned firearms without an FFL, but you cannot actually have a dealership or gun selling business without it. Different states may have different regulations, particularly on the transfer of handguns (states with a pistol permit system may require a pistol permit to be submitted even in a private sale, while some states strictly require all private sales of handguns to go through an FFL dealer).
No. Absolutely not. If someone purchased a handgun from you, and it requires shipping, you can only ship it to an FFL licenced dealer, who will receive it for them. Before shipping, you must obtain a copy of their FFL (Type 1 or Type 2).
Yes. The online seller doesn't ship it direct to you - it goes to an FFL dealer who handles the Form 4473 and transfer.
See related link. Always wise to call ahead to see if they have one in stock. If not, they can usually order it, or you could buy one online and have them do the FFL receiving for you (in which case, you'd want to find out their receiving fees beforehand).
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.
Blackpowder guns are exempt from the Gun Control Act of 1963. This is the law that requires a Federal Firearms License (FFL) to send guns by mail. So, no. You don't need FFL to mail black powder guns.
Depends on WHICH FFL you want. The BATFE requires that you comply with LOCAL laws before they will issue the license, That includes things like zoning, business license, etc if you are looking at a business FFL. You will need approval from local Chief Law Enforcement Officer for a business FFL. A Collector's FFL (03 C&R FFL) requires only that you send a copy of your application to the Chief local LEO.
No! Not unless you would be in the business of also selling firearms.
No, you can purchase it the same way you would any non-C&R handgun without the Type 3 FFL (C&R).