Form 4473 and NFA Trust Questions

I'm currently waiting for my first NFA item (Mk. II SMG) to be approved. I expect that it will be any day now.

I have a question regarding the 4473 that must be filled out prior to taking possession of the NFA item. Who is responsible for filling out the Form 4473 in the case of an NFA trust? Is the trustor the only person who can fill out this form or can any of the co-trustees fill out the form and take possession of the weapon? Also, if the SOT chooses to do a background check, can a valid concealed weapons permit take the place of the NICS check or does the ATF require that the phone call to NICS be made or is this up to the individual dealer?

Thanks for any insight you fellas can give me.

I'm really looking forward to some full auto fun. The journey has been interesting and I plan to do it again when finances allow me to do so. :D

Edited to add: Apologies if this is in the wrong forum.

Really good questions. Depending on your state, it is usually trustees/grantors that represent the trust for pick up. The NICS check thing is a conundrum because the 4473 still says that NFA items do not require it. ATF's "requirement" for a NICS check for the trust is a bit tenuous at this time. Still, I would lean on the side of caution, not knowing how this whole new rule thing is going to work out. Have your dealer run a NICS and record the proceed number on the 4473...