You do need to take homeowner education training (online) and landlord education for 2-4 unit properties. 

Are there any online and/or national banks that are open to this very low risk proposition where I can find an interest rate under 4.5%? 

You can also check their reviews online at Google, Facebook, or Yelp.

More than likely your best bet is to just keep everything the same. 

They can also work on getting their brokers license and open up shop.As far as qualifying buyer YOU BET I send them financials to fill out before jumping on a call with them.

If you cant refi my bet would be to pile up the cash in a separate account so that you can build up a nice down payment for another duplex. 

In this day an age, syndications are done online and its called crowdfunding.

I bet most of these guys in your area would know just by the address what the potential for asbestos would be and possibly could alleviate your fears by a simple inspection. 

As new units came online existing tenants saw the writing on the wall and began looking for new places.  

You could use the BP calculator (5 times for free membership) or find some available online for free.The most important thing that is going to get you ahead: commit to do 1 thing at least every day that is going to get you closer to your goal of acquiring and creating wealth through real estate: read, analyze, go to open house....Hope that helps.Good Luck