Correct, under the new law le sign off is no longer required. They do require a notification, but I think that it’s done automatically from the kiosk.
On my trust I have 1 in OKC, 1 in Tulsa, 1 in Denver, 1 in Fort Collins, and one in Heaven. So getting everyone on board for pictures and finger prints would blow.
Not sure about adding someone to the trust, I believe you are correct until you add another item. But I could be totally wrong.
If you wanted a new NFA item couldn't you remove everyone except yourself from the Trust and then fill-out the forms, fingerprints, and photo of yourself, to purchase the new NFA item? You could then add back whomever to the Trust? I'm assuming all NFA items are in your possession.