-AlexYou’ll be able to qualify for the tax deduction and the Like-Kind Exchange based on how you structure the deal, but yes to both possibilities  

On a related note, and I am running it by my CPA as well, but was just curious if anybody had issues deducting interest paid on seller finance deal?

They just expect it to support their lifestyle once they stop working along with some tax deductions. 

It could help accelerate depreciation deductions, especially with your mix of single-family homes and duplexes.

If you have 80 some rentals already that you bought years ago, I am guessing that the depreciation deductions are running a lot lower now for those units and you're probably paying higher taxes. . .

Each year at renewal we ask them what we can do to make their place better, maybe painting a room, installing a new fan,  .. anything up to $200,  so they tell us what they want, and it's fully tax deductible.  

You are eligible to deduct the interest regardless of the type of loan(Bank or seller financed).Best of luck

I assume you deduct it over the next 5, 7.5 and 15 years?

Make sure the deposits are transferred and not deducted from purchase price, otherwise you will need to come out of pocket when tenants move out.You should also make tenants and landlord sign an estoppel agreement, which outlines important items and agreed to, so the tenant cannot claim to have a huge deposit later or claim that the prior owner gave him ownership of the shed in the backyard.

@Robin Thornton Whatever calculation you decide, make sure to include your insurance deductible on top of whatever you budget for repairs or vacancy loss.