I don't believe you would properly replace the debt in this situation.

Many DSCR programs require an investor to have a mortgage history- there are some DSCR mortgage programs that will work with investors who are renting- some refer to them as first time home buyers (FTHBs)- DSCR loans are only for investment properties where the owner isn't living there. 

The mortgage and property taxes use up most of the income from rent.Don't focus on the number of rentals, focus on the quality of the rental. 

Also, credit score minimums are higher- often requiring a middle mortgage FICO score of 720 and above.

While the 4% mortgage is great, your 1M in dead equity isn't giving you a great return.

Capital gains are calculated as:Sale Price - (Original Purchase Price + Capital Improvements + Selling Costs) - depreciation (if applicable) = Capital GainYour mortgage or HELOC balance does not affect this calculation—it only determines how much cash you take home after the sale.In Massachusetts, if the home was your primary residence for at least 2 out of the last 5 years, you may qualify for the Section 121 Exclusion, allowing you to exclude up to $250,000 (single) or $500,000 (married filing jointly) of the gain from federal capital gains tax.

Does that factor in both the mortgage, taxes and maintenance? 

Using mortgage debt at 6-7% on a refinance to pay off higher rate debt such as a credit card at 15-25% is a savings!

that we’ve learned in our 24 years, managing almost 700 doors across the Metro Detroit area, including almost 100 S8 leases:Class A Properties:Cashflow vs Appreciation: Typically, 3-5 years for positive cashflow, but you get highest relative rent & value appreciation.Vacancy Est: Historically 10%, 5% the more recent norm.Tenant Pool: Majority will have FICO scores of 680+ (roughly 5% probability of default), zero evictions in last 7 years.Class B Properties:Cashflow vs Appreciation: Typically, decent amount of relative rent & value appreciation.Vacancy Est: Historically 10%, 5% should be applied only if proper research done to support.Tenant Pool: Majority will have FICO scores of 620-680 (around 10% probability of default), some blemishes, but should have no evictions in last 5 yearsClass C Properties:Cashflow vs Appreciation: Typically, high cashflow and at the lower end of relative rent & value appreciation.

DIRECT MORTGAGE LOAN COMPANY6.