Re: trust backround check?
You are buying the suppressor as trustee of your trust and assigning it to the trust using an assignment sheet. Your wife cannot have access to the suppressor, except when you or another trust member are present, until she is 21, therefore she can't be on the trust until she is 21.
You can add people to the trust, as co-trustees/settlers, at anytime, but since it is a NFA trust, they must be of legal age, and meet all other legal requirements to be in possession - non felon, etc.
Legally she can't even have access to the safe that the NFA item is stored in until she is NFA legal and a co trustee of the trust.
I recommend you go through a lawyer with knowledge and experience in NFA trusts. My Son and I went that route and it was worth every cent.
It is also recommended that only NFA items be assigned to the trust.