I can help with some of the bits you want.
I have headlight from shell, rim, glass/reflector to a complete unit.
I have both European and USA B rear mudguards. Both are solid but will need re chroming or painting.
I think I have a front B mudguard but will need to check. I also have CSR/LTD front mudguards which although a different style I believe they will fit.
I also believe I have the choke housing but again need to check.
I am afraid as far as original B exhausts are concerned we all just dream. They very rarely come around. I have even struggled to find a knackered set so I can see about getting some made.
Let me know if your interested.