We have one of the most undervalued purchase markets and one of the highest rental markets, a good recipe for success if you position yourself correctly. 

The Short answer is this: While you are correct that you would be paying down the balance of the mortgage you would not however be in a position to pay for any surprise that might come up and need you attention and you money...

Depending on the lease you used your document may have a transfer of ownership clause or something similar which requires your consent.If you do not have a personal guarantee or some sort of material change or adverse change provision, I am not sure what recourse you may have with the sale of the business operation.

If you think you'll sell your current properties in a few years, build up the equity and pay them down now so you can be in a better position to roll the money from those sales into other properties.

How does the market look for appreciation in your equity position in the property? 

If the new Buyer reneges, that might put the OP into a better bargaining position!

Now, at some point there may be some risk w/A properties overbuilding, but we target primarily B/C properties in these good areas, do value add / re-position in infill areas where we can continue to keep rates slightly under market for the demographic we are targeting.  

For the last 3 years, I've finished 2nd place for full time NBA positions that 100's of applicants interviewed for.

Looking to be in a position to acquire 10-15 additional assets by May/June 2017.

Your primary concern is mitigating risk.