Tired landlords and conventional loans weren't available.   

The modeling of this is actually pretty easy (see link: 42-unit proforma sample), but my model treats the pre-refi loan as I/O, but that can be updated based on your deal.

I was also on the construction loans..

You won’t find many seller-financing deals here, so if you're looking to scale quickly, your next best option is the BRRRR method—using cash or hard money to acquire properties and DSCR loans to refinance into. 

You can allocate those proceeds any way you want - as equal down payments or buy one for cash and others with loans - It doesn't matter a bit as long as you use all of the cash and purchase at least as much as you sell. 

Quote from @Vince Scipione: Standard would be an FHA loan for your situation more than likely.

I've helped people with SBA loans to purchase real estate for a business, but for buying rental real estate, the DSCR loan is a much better option.

Is there a pre existing loan with that bank with either of you?

If you Bank/Lender does not allow it you can refinace the mortgage into a DSCR or true Portfolio loan program. 

@Steve Powers is correct that these were mostly originated as owner occupied loans.