Hey there!
Although we do not require the existence of an Advisory Council, we do highly recommend it.
In our Model A contract we refer to the it as the Project Committee which would be an internal committee formed to help manage the day to day operations of the programs.
My two cents. The Project founder (individual or on behalf of an unincorporated nonprofit association) should directly sign the agreement and part of that agreement establishes the general legal role of a Project Committee. You could then have individual members of the Project Committee sing something that says they have read and understood the fiscal sponsorship agreement and will abide by the policies. @Stef Flores posted a somewhat similar question recently and I put some more thoughts there - might be useful… #Steering Committee Agreements #comment