Pretty typical in commercial in my market for buyers or tenants to pay their own agents.

Majority of the buildings are typically older units so you you need to adequately put aside for capital expenditures. 

What is typically done on BRRRR?

Do I use a home  equity line of credit that I have on another rental at 6%  or do I use my  saving earning 1.75%?

However, by the time the appraisal is released the buyer is typically into the property for at least a few hundred dollars.  

Typical is $500-1000, but only if they close the deal.

Let's also say together we purchase a multifamily @ $1,000,000   I understand the prohibited parties issue.1) If we (myself and the SDIRA) were going to put 20% down...does that have to be in equal amounts meaning 10% from me and 10% from SDIRA and everything is split 50 / 50 or can you still have normal deal partnership flexibility...so something like the SDIRA puts in the entire 20%, owns 50% of the property but gets a "preferred return", etc.2) Perhaps the bigger question is financing, I know there is SDIRA financing that is non recourse but that is typically for 50% LTC. 

Typically you'll need to make a larger down payment.

I have come slightly close to getting out all of my initial investment in the short term but I have not gotten out all of my investment (purchase + rehab) out due to 1) typically we do not get 80% LTV (we typically get 70% LTV) 2) the refi appraisals come in below market value (common issue in san Diego).Therefore I have yet to achieve the infinite return in the short term. 

The monthly savings typically outweigh the additional insurance cost.