Just a note (and this is meant in the spirit of friendship and not criticism): Call them NFA firearms. Calling them "Class 3" will make you stand out as a noob.
A Class 3 Special Occupational Tax is an additional endorsement needed by a Type 1, 2, 7, 8, 9, 10, or 11 FFLs to sell (but not make or import) NFA Weapons. You could just as well make your NFA weapon yourself or buy it from a Type 7 or 10 FFL who also has Class 2 SOT (manufacturer and seller). There is no such thing as a "Class 3 firearm".
Mike
PS. We don't know what will happen with trusts (I have some questions about their ability to reinterpret the statutory definition of a person) or how long it will take: the regs to ban bird bombs took about 9 years after Congress passed a ban (with a relatively unambiguous intent to ban them in the statute). What we do know is that there is a ton of uncertainty and that is no doubt driving up the amount of applications and increasing delays, probably greatly, even if nothing happens.