And we started logging progress and availability on a company FB page, cross promoting to local swap pages, and now we have people asking when our next property will be available.

Juliano Pereira So it looks like 3-4 families are not counted as residential in this regard

I've made a decent living over my brief investing career in Austin, but I've warned many out of state investors to the same thing that @Jay Hinrichs mentioned, which is that we have no state income tax here, which means that our property taxes are astronomical to make up for it.If you live here, it's immaterial, but if you live in a state with income tax, you're essentially getting taxed twice (and yes, I'm aware of (some) of the complexities of cross-state earnings and how they're taxed).

So should the vacant lots be counted in the purchase value, and if so, how?

However there are several exemptions under to the non qualified usage time listed: https://www.irs.gov/publications/p17/ch15.html https://www.irs.gov/pub/irs-pdf/p523.pdfThat indicate that Any other period of temporary absence (not to exceed an aggregate period of 2 years) due to change of employment, health conditions, or such other unforeseen circumstances as may be specified by the IRS does not count as non qualified use.

Crossing years complicates financial reports at year end. 

Seasoning for Refi is mostly just applicable if you're looking to count the rental income towards qualifying income for the refi mortgage.

The property in this area would not increase much I would not count on it.

My question is if this will be counted as a monthly debt for my dti ratio for a home purchase down the road.

Count me way out.