Alabama - super low property tax but the rents are lower as well but all in all a good cash flow state.  

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?

Timelines, budgets, quality of finishes, they all need to go well for your exit and if your in bed with a GC that only cares about himself then all those things will not go right for you, but he'll still get his money.People really underestimate the following:1) The cash they need to close and carry the project2) How hard it is to have a GC stick to what they promise3) How long it may take to exit through a sale

So I would agree to instead get a lender that you can scale with.But it looks like you got a credit union to give you a good rate, better than most as well 

Having a local trusted partner to manage your investment properties is key as well. 

Could you please provide insights on these?

It costs roughly $100/mo but is well worth the expense.  

if you were only going to rent out a portion of the house as an STR that portion would have to be worth more than your exchange as well.

My thoughts as well.

You should check with your 1031 provider quickly.