If predictable appreciation is in the cards, that changes the equation but I would still recommend bench-marking it relative to other investment properties.If you are willing to house-hack as you mentioned with the duplex, that is an excellent way to get started in REI.  

I'd recommend calculating your future expected returns for both types of properties that you are buying, include appreciation, and bench mark them relative to one another.  

Almost every house over 100 years old has a "Pittsburgh Pot"....The toilet in the basement often in the middle of the floor.

In order to “sweeten the pot” I am considering offering the property to him at $70,000 cash or $80,000 and I carry the mortgage at a below market interest.

But even these poor performers put some money in the pot for the next deals.BTW, on the high end, I got a total return of 181% ($100K in and $281K back) in 19 months and a total return of 380% ($125K in and 475K back) over about 6 years. 

After spending months and months reading post after post and listening to podcasts seemingly all day long, I decided it was time to get off the bench!

Is the RE equlivent  of “what do you bench?”

I personally would never give that info to a potential landlord ..And while of course as landlods we need to ensure we approve tenants that will pay their rent and not damage the unit,  whether someone drinks, smokes pot or dresses up as superman  is none of my beeswax - as long as they meet my screening criteria ;) I actually think I checked social media on only one applicant.

I assume you were smoking pot?

Hope you all had a great year in 2018 and you made pots of money.Just curious what and where you will be investing in 2019 if you care to share