Being a wholeslaer is having a business.You are in the business of finding and buying land/contracts for a short duration and then immediately selling them.One typical expense for a wholesaler is all the advertising costs to find motivated sellers.

I'm in Tampa, FL but focus on fix and flips in the Fort Myers-Naples area with my business partner since 2021. 

For example, a quiet neighborhood that used to be a busy factory area might have hidden issues, like pollution.

Myself, significant other, and my close friend/business partner have been renovating his personal residence for the past few months with the intention of renting it soon.

Just like with a residential mortgage would they need business tax returns as well for add back purposes?

The length of holding only matters AFTER you already determined it was a capital transaction, as opposed to a flipping business.Step 1: business or investment?

Myself, significant other, and my close friend/business partner have been renovating his personal residence for the past few months with the intention of renting it soon.

My thought was also to just rent the lot itself as it's located on a pretty busy lake. 

CRedit Union or personal business line of credit at a lower interest rate would be best!

I never give out my contractors name for renovations because I keep him busy enough and he also has many other projects.