New builds are far more desirable, and have less total cost of ownership than many of the stick framed, pre-existing, non conforming older homes. 

(In Texas you need AC. ) We had a house we just redone for a rental and it was an older house with no pre-existing ductwork.

Are you trying to convert a pre-existing room into a bedroom to increase the ARV?

Other than that though, my main question is if the land isn't to expensive, will building come out to be cheaper than buying preexisting.

Even when you exclude the ones who are simply renting out their own spaces - second homes, pre-existing ADUs, spare bedrooms, or their RVs, the number of people that started with less than we have is likely still significant.

Also when wholesaling you should be turning to a buyer you have a pre existing relationship with.

To register, an owner must provide a completed application, proof of ownership, designation of a responsible party, a copy of the City of Bradenton’s business tax receipt, a current and active license as a TPLE, a current certificate of registration from the Department of Revenue, an exterior site sketch, an interior building sketch, a blank rental agreement, and any pre-existing rental agreements.

Which are more prevalent in Santa Fe single family properties: pre existing ADU's or a potential to add ADU?

We are choosing new build because A) our family 4 has a certain size demand B)  the price-quality ratio doesn't seem to make sense when considering a preexisting home C) with interest rates being at near 8% with preexisting homes, builders are offering 5.99% interest rates and the exact home we are looking at is about $75K discounted because it's a spec home and the builder doesn't want to pay taxes on it.So, live in it for 5-6 years hopefully rent it out with a fully finished basement for potentially $4,200 in 5-6 years.

The pre-existing condo conversion was super easy as it already was a multi-family, so the de-facto split already happened in the past.