After examining the analysis I had done on his offer and then taking a look at my counters from the view point of a buyer he realized that what he was asking for it was a waste of time and if he were to put it on the market and try to sell it to a stranger nobody would want it with his numbers through seller finance. 

Examine off-market purchases; they may have greater possibilities and less competition than MLS listings.

The risk is high that they will be recategorized by the IRS upon audit or examination, which means that you've overcontributed to a retirement plan. 

Examine several funding choices, including partnerships, hard money loans, private loans, and traditional mortgages.6.

@Kim LeJeuneThe economic reality of the contract must be examined to determine whether you have a purchase option or deemed sale. 

@Aldo BalattiIn the markets I have examined, traditional PMs don’t make sense when examining SFH.

A follow-up question: What resources do you use when examining a potential market area?

So any attempt to bargain sell to save taxes for the mom will result in a failed exchange if examined.2.

Make sure you account for unforeseen costs and emergencies in your budget.Property valuation: Examine recent comparable sales (comps) in the neighborhood to ascertain the duplex's fair market worth.

Again, others might feel differently here.3) property level due diligence: (takes seconds to weeks per deal): here is where I drill in with the low-level details.a) pro forma popping: I examine all the assumptions, and see if they are overoptimistic or not.