My goal is to start with a house hack on either a single-family property with an ADU, a duplex, or a quad.

., "I will buy at least one single-family home, duplex, triplex, or fourplex before the end of 2019") and then do it.

Most users of VRBO have one single 5-star review, thus our threshold is lower. 

it will be a corporate/wellness retreat/short term rental destinationI need land that is close to the Action, but not too close, and preferably comes with two single family doors already built, so I can take advantage of Fannie Mae owner occupied loan and develop the rest of the land on my own and with private funding.Is Columbus a good market for this strategy?

Mortgage lenders will qualify you for a higher purchase amount for multis than they would on a single, because they will count the rent you will be making on the other units as additional qualifying income for your loan application.

Issues 1) even garage conversion ADUs in single family zoned areas typically cost more to build than the value that they add.  

The last year I renovated a single family home to rent, pulled out some equity, couldn’t have gone better.

got out of flipping to new construction in our market in columbus ohio. licensed general contractor. when interest rates got high single family existing went down by 30% new builds sold at a 6% increase that year which demonstrated the desire and premium that new construction commands. never looking back. total control, rinse and repeat. we can get permits in 28 days. we can buy land cash in 21 days. we can build in 120 days to 140 days and keep moving. super scalable and easy and no risk. we build the same 2-3 Floorplans 

There are more factors than just the community (#beds, level of theming, location to the amenities, style of home (single family, townhome, condo) and others) But I would strongly advise to stay within some of the same communities you mentioned like Storey Lake, Windsor Hills, Championsgate and a few others if cash flow is your goal.

I have 4 single family homes rented and rehabing 2 currently, in the pee dee area.