I have some questions around paying the mortgage and also about the use of a business credit card. 

Your local banks will likely have more strict underwriting rules than credit unions.Online mortgage lenders are increasingly flexible and might provide HELOCs for investment properties.

But they also take a "buyer/renter beware" stance and their view, based on my interactions with building department and section 8 inspectors is: as long as the house does not have cracking or chipped paint, the chances of it effecting people is basically non-existent.  

I was looking for specific companies that don't seem to exist.

There are mortgage programs in VA, DC, MD that could get you in a property with a very low downpayment.

Whether or not your existing policy would provide coverage may depend on:1. type of policy2. are you charging for the rental3. are you renting to a non-tenantIf it is covered, you need to work out waivers and contract language with your attorney. 

1) You would pay tax on the sale of the properties(assuming there is gain)2) You would lose out on the mortgage interest deduction for the properties being paid off which may increase tax burden in the future.

Why do I see some independent mortgage loan officers submit borrower's application directly to lender without going thru their employer/broker's loan processing?

Here's my experience summarized about the Midwest. https://www.biggerpockets.com/forums/48/topics/1165499-whats...The "cash flow on paper" for Class C Midwest (which is almost non-existent with 7% interest rates) will cost so much in repairs, capital expenses, tenant issues and it won't appreciate enough to make up for the losses.

Here are a few suggestions:Interest-Only Commercial Loans: Yes, interest-only commercial loans do exist and might be a suitable option for your situation.