For example, Sevastopol passed an ordinance that restricts stay durations, effectively prohibiting short-stay, high turnover properties.

But here is the result of the negotiations and the final deal I signed.Amount owed to bank $690k   Price I paid $468.7kTerms - Prime floating - currently 3.25%, 2 year deal with 2-1 year renewals of the sameThe loan is I/O and debt reduction is straight-line taken down at the commencement of a construction loan.The bank is to finance 1 spec home at a time during the duration of the loan.

We would like to stay out of the house for the duration of construction as I have allergen related asthma issues.  

1. what is a reasonable contract duration?

I wish there was a place where appreciation and property taxes were tax-advantaged like a retirement account, so that my "buy" price (after I've paid my taxes on the income used to buy it) is primarily what establishes any future property taxes I would have to pay, no matter how much the asset increased in value, over my long-term ownership of the asset, so that I'm not double taxed on my income and then taxed AGAIN based on the future increased value of the asset I purchased with that income.It would be completely mind blowing if such a place existed, making that place truly unique for real estate investing, on the global stage, even so much so that a bunch of Billionaires from East Asia might want to buy those assets because they've found the best place possible to park money for long-term growth, while receiving CoC ROI for the duration of their ownership, compared to anything else on the planet Earth. 

And if you mess around just a little with some of your assumptions and go with $180/month in cap-ex and 18 month average tenant duration you really start to change the ROI numbers.  

Some mortgage products may be available to you with a larger down payment and just consider that extra money invested as a savings as you can refi out later once you have the work history duration. 

You said you and your wife plan on living in it for the duration of your next tour so I don't see that being an issue.

If you are not comfortable with that then buy short duration front end payments where the seller still has a substantial interest in the latter payments so they will be motivated to look out for your interest, or buy out your interest, in the event of default.

It could be that there is no minimum duration or the minimum duration is  very short.