Dear Joker,
Having had, for a brief moment in history, the dubious distinction of being the youngest FFL dealer in the country (got it right after my 21st birthday), and having dumped it due partly to the paperwork inconvenience and my own lack of maturity at the time, I have a little insight.
Now, keep in mind that my information is almost a decade old now, but I can answer a few of your questions:
1. Nowadays, the ATF is very picky about FFL's operating out of their homes. When I dumped mine, they were making noises about "Inspecting My Place of Business" and when they found out it was my home, they wanted a floor plan.
I don't think so.
[:(!]
2. SOT stands for Special Occupational Tax. That's what the "Class 3, Class 2" sort of thing means. It's not a license in and of itself; It's a tax paid by an FFL holder to transact business in NFA (National Firearms Act) weapons, such as fully automatic firearms, short barrelled shotguns (SBS's), Short Barrelled Rifles (SBR's) and Any Other Weapons (AOW's). Definitions for these can be found, if I recall correctly, under Title 18, Chapter 44, United States Code. But back to the SOT: They (The ATF) issue you another piece of paper that looks a lot like a license but is actually a "Tax Stamp", with the amount paid and which SOT it is. There are three classes: Class 1 is Importer, Class 2 is Manufacturer, and Class 3 is Dealer. For any and all NFA weapons (guys, correct me if this has changed).
3. Getting an FFL gives the ATF very specific legal authority to enter and search your place of business any time they feel like it. If this is your home, you are giving up some pretty serious constitutional rights. THINK about it.
[:\]
If you have given all these things their proper consideration, and still would like to do this, I recommend getting a storage unit or other off-premises location, or rent an office from someone else, wherein you can keep your "business". And get a really good safe.
Best of luck to you,
Panz