Bottom line - All hype, bs, misinterpretation, opinion bias, etc aside, sellers willing “owner finance” the sale of their property for one reason - and one reason only: They PERCEIVE that they are getting a higher price for their property by owner financing than by a cash (cash to them) sale.The “perceive” part is why buyers can sometimes structure terms ridiculously one sided in their favor - because some sellers are so focused on PRICE they become oblivious to anything else.It’s why I and numerous others have been able to structure 20 year owner financing loans at ZERO interest; why sellers have accepted “substitution of collateral” that gave them a lien on recreational land I had rather than their own income producing property; why sellers accept second position liens and allow buyers to obtain new first mortgages ahead of theirs (subordination), and why sellers always accept mortgages without my personal guarantee.I myself sell properties and provide owner financing to obtain a higher price.

That is acceptable by our fire dept in Denver that inspects it once a year. 

Beyond removing the developable parcel from existing loan expect whomever finances the construction to want zoning, building permitting and utility connection approvals before the loan is originated (some will accept just zoning).

After giving notice to vacate or filing an eviction suit, Landlord may still accept rent or other sums due; the fling or acceptance doesn’t waive or diminish our right of eviction or any other contractual or statutory right.

The key is to test, test, test until it works.

Reserve requirements vary greatly from lender to lender but you have to acceptable reserves of some sort as well.Lastly, keep in mind, many lenders will not consider managing properties where you are not on title as experience. 

I found an inspector to do a walk thru before my offer was accepted.  

Recently, PM suddenly told me that this property needs "lead testing".My PM is not aware of this I already have 2-year lead certificate from the previous onwer AND assigned an inspector for lead inspection for me.

It sounds like you are mashing a lot of different things together here.It does not matter at all if you have an LLC, or if you, or your wife is the owner - it doesn't change any of the tax positioning in the slightest.The test to be a qualified Real Estate Professional is at least 750 hours in real property trades or businesses AND  over 50% of your professional time. 

I had about the same results when I placed 20-30 calls per day, and the quality of the leads were similar: every day I would speak with 5-10 individuals and get one or two seller saying they are open to the idea of selling their house, but they would not accept anything less than the full retail value (often 125% of Zillow estimated value).