Hi @Alex Lee I would avoid 203K loan and work with conventional renovation loan based on knowing you'll be forced to use 203k certified contractors which will cost more money and offer inflated pricing because they must follow 203k guidelines. 

You have the money, but you really want to buy it with a loan for some reason.

All together around 80k worth of money invested.

By donating the owner will have the money they want.

But now I'm thinking of renting the whole house and getting a cheap apartment to save even more money.

I assume any painter / handyman doing your turnover could do that kind of touch up in almost no time for almost no money.  

For the most part, most lenders are going to be relatively close in cost assuming we are talking about a straight forward loan product, we all borrower from the same pool of money to make these loans. 

I know exactly where this duplex is---in Broad Ripple over by Mama Corolla's and the Liter House.John Jacobs Real Estate Investor and Private Money Lender  Indianapolis, IN

Generally the thing that keeps commercial/industrial investors afloat is access to large sums of money to survive a downturn.It sounds more like this property is an outlier in your wheelhouse and portfoliio. 

Flipping houses is a great way to create huge profits, raise private money and create marketing content around your remodels (the reason HGTV is HGTV).