#2
From what I know you'd have to drill a few holes in the guitar. I'm not sure which model bigsby would fit. Honestly I think it's more trouble than it's worth, but that's up to you.
Gear:
Gibson SG Special Faded
Marshall JCM2000 DSL 401
#3
Yes, you could definitely put a B-5 on there. If you don't want to drill holes in the guitar, there's a company that makes a little device that keeps you from having to drill. I'll go find the link for you.