If you are working with a licensed real estate agent under an agency agreement, (i.e., a conventional, full-service commission agreement in which the agent agrees to represent you), your agent will be bound by common law (in most states) to a fiduciary relationship.

The NAR settlement doesn't change anything, besides the need to get a buyer agreement signed up front. 

Home365 quoted me by phone last week 7% monthly management fee and 50% placement fee for their "Standard Plan," but their WRITTEN Prop Mgmt Agreement actually lists many fees and limitations.

Operating agreement, subscription agreement?

Follow your split agreement.

Would I need to re-write the operating agreement if it was not previously used for real estate?

I've considered an assignment / option agreement / not sure how to structure these.  

Please give me feedback as this doesn't quite fit into typical calculators and I'm not confident with my current calculations.I have signed an off-market Agreement of Sale (executory contract) on a property in the Phoenix suburbs. 

On the one hand, I know they are all anxious about what the new terms will be - perhaps I should tell them ASAP (I move in at the end of this month and have a lease/occupancy agreement with the owner until then).

Everyone will walk away feeling OK if you amend the original agreement.