We're just using a product that most banks offer.

Both have portfolio products.

So, if the plan is conducting a business such as flipping houses or owning a portion of a business run by others that provides a service or product, then UBIT can apply.

There is no timeframe on that; although most buyers want to buy a finished product.  

If only option was to rent the top as a 3br, numbers are still favorable for the product in my market.

It may also be used by some lenders for other credit product application evaluations (such as credit cards, personal loans, retail credit, student loans, etc.)."

Many lenders have asset depletion products and some portfolio lenders will consider Schedule D income.  

Are you seeking best lender or best product?

@Jonathan Rivera I agree with Melvin Noriega's answers, however the VA loan is not a great product for a few reasons. 

Reach out to your broker contacts and your network and ask for lender referrals that play in the apartment space.Your pre-screen interview calls could includ asking them if they do apartment lending, what their typical loan size range is, what class of property do they like, standard loan terms (amortization, fixed rate period, interest rate range, LTV, and any other product knowledge you would like).