As a buyer, really don't have direct control over how your agent is compensated.As a seller, @ jonathan greene covered it pretty succinctly.

As you know, moisture/ air/ vapor/ thermal control is key for the long-term performance of your house and occupant comfort. 

If you have a clear division where 1 person controls the LLC then you can transfer the properties in and out (quitclaim deed) of the company in order to refinance. 

That is something out of their control.

However, a large amount of the work that dictates if you can close in under 30 days or not is under your control. 

focused on that booming business of hers (hey, and power to her btw), a new real estate venture represents risk that she has no incentive to take on (she can ALREADY put $ to work earning 50%!)

Since there's rent control, it'll take years to get to market rents.  

The few times I've had a buyer go unrepresented I would venture to say it is more work than if they had an agent. 

Can anyone tell me the best way to structure a joint venture with a silent money partner?  

It's much easier to save for a downpayment and invest once you have your debt under control and you are now "house-poor".