A few financial advisors will compensate Deliverables Team Members for their efforts directly (with the compensation you receive from your clients).  If you are compensating Deliverables Team Members directly you will need to have an attorney draw up a clear agreement of services to be provided as well as client disclosures.

For the rest of you, most, if not all, of their Deliverables Team Members  will bill for their services directly to the client.  In this case, where your Deliverables Team Members charge your clients directly for their fees, a "handshake agreement" with you might suffice.

However, in both cases you will want your new Deliverables Team Member to create a documented process for every client deliverable expected from them (using The Best Way™ method we teach on The Trusted Advisor Toolkit™). 

In most cases, your new Deliverables Team Member will assign an administrative support person in their office to view the quick video lesson on The Trusted Advisor Toolkit™ and download The Best Way™ templates to document the timetable & instructions for how information & documents will be passed between your offices for each deliverable. In other cases, you may need to assign your Administrative Manager to help them document how each deliverable will be accomplished prior to the due dates.

So, regardless of whether you have a formal agreement or a "handshake agreement" the most important thing to document prior to working together are "the processes." 

After that, you should have clear agreements regarding other obvious issues, such as confidentiality, who "owns the client," the Deliverables Team Member's willingness to serve as a part of your team (rather than as a "single gunslinger" Subject Matter Expert), and an understanding of under which circumstances they would ever consider referring your clients to another advisor.