I have not done it personally but have some insight, maybe my reply may boost your post to someone with more experience in it. 

If I understand correctly; the seller would receive 80% ($40,000) directly from the mortgagee at closing and would enter into a personal agreement with me for the 20% down payment ($10,000) in which he would be reimbursed separately from my mortgage payments at a separately agreed upon rate and term?

I personally like the buy-and-hold strategy and we help clients who share this long-term, wealth building mindset. 

With a Conventional Loan you can buy a SFH, Duplex, Triplex or Quadplex with as little as 5% Down if it is your primary residence as long as you have the intention of occupying one of the units for 1 year after closing escrow.This is the strategy I have personally implemented and have assisted many of my investor clients in doing the same. 20% Down is also beneficial as it keeps your payment low but it does limit your ability of buying more real estate faster.i would be more than happy to discuss the different strategies with you over the phone or in person.

Thanks, Jim Rice in person or online?

I financed the acquisition of the land with personal and private money.

This person (not Blake capital) was trying to bully me (wrong move).

Personally, I'd go with the As-Is scenario.

Be prepared to follow up multiple times, using different forms of communication—calls, emails, and if possible, in-person visits to their office.

You'll want to put together a personal financial statement (basically lists of all your assets and liabilities) and have your tax returns ready.