How much do they want you to to pay, to pay off one of the mortgages (or both of their existing mortgages)? 

. $1300/month, tenant pays all utilities. 4 bedroom one is vacant.

@Chinku Chinku how is paying the loan balance down going to help you reach your goals?

We will be paying nearly $50,000/year in property insurance.

If rates come down (most likely not in 2025) you can refinance or just shovel cash-flow and pay it down quicker. 

Right now, the best offers around me are for some 1.3-4 million, that only generated around 100k per year gross, so there would be a high chance of not cash flowing, and paying money, especially with a commercial loan (these buildings have more than 4 units).I was thinking that although the rental itself does not generate money, I would be able to deduct the mortgage interest, and depreciation from my personal w2 income and would be net positive.

Why pay off the mortgage early? 

Ask your employer if you can have your pay split up into three deposits, one to investments savings, one to your checking account for personal use on a daily basis, and one to an emergency account you can tap into so you don't have to tap into your investment savings.

The only way to pay down a loan, is to pay down a loan.

And, it's amazing how many closing costs are junk fees that we as investors need to pushback on paying for ourselves and our clients.