-I'm curious to hear how you arranged no down payment for this loan at a 3.6% interest rate, since these terms are shockingly generous. 

That’s a pretty good arrangement in my book.

If you feel like you have extreme unity with this person and this is a person you would choose to be a foxhole with and they just so happen to be a great handyman that you need for your PM business then that could be a killer arrangement. 

As a California real estate assistant, it sounds like you're allowed to do the following:-cold-call prospective customers (although not regarding a specific property, transaction, or product), -assist with open houses,-conduct a comparative market analysis (i.e. identify comp properties), -arrange appointments, -give entrance to a property to inspectors or other authorized 3rd parties, -prepare and design advertising, -prepare documents and transaction instruments, -deliver and obtain signatures for documents (although you can't discuss the contents), -accept money for trust funds (i.e. earnest money or similar), -relay certain information between the agent and the principal, and -review transaction documents for completeness and compliance.Hope this helps. 

Assuming we go on to do other deals together and considering tax advantages/disadvantages, how would you rank these deal arrangements, and what do you think are fair or ideal numbers for A, B, P, Q, X, Y?

These are referred to as "tying arrangements" wherein the real estate agent ties the purchase of one product (property management) on the condition that you also purchase a different product (sales).

For example, the furnace crapped out, and he arranged to have it replaced (which is fine) but also charged me $200 for bringing 2 heaters to my tenants for 3 days.

I arrange the deals and do everything.

Please let me know when the sellers’ have arranged for a 3rd party to review the damaged hardwood floor and have a proposed time available for an appointment.

You as the "Working Partner" find the deals, arrange financing, manage rehab if needed, find and place tenants and do all ongoing property management and business management.