We ended up obtaining a HELOC on our primary residence with a local CU. 

I obtained my GC license in CA about 10 years ago so things might have changed a bit since then, but as I recall you needed to show you have sufficient experience in order to apply.  

My main question to BP would be what are ways I could finance to help me reach my goal of obtaining a duplex/triplex?

If those 2 individuals from who you obtained quit claim deeds are in fact heirs, then you own an interest on the property regardless of who paid the taxes.   

I just recently obtained my RE license and am currently looking to go after a particular niche.

Anyone dealing with BK and foreclosure fallout knows about the wait times, HTH.https://www.fanniemae.com/content/announcement/sel1410.pdfhttps://www.fanniemae.com/content/guide/selling/b3/5.3/07.html"If a mortgage debt was discharged through a bankruptcy, the bankruptcy waiting periods may be applied if the lender obtains the appropriate documentation to verify that the mortgage obligation was discharged in the bankruptcy.

I'm a licensed real estate agent in MD, currently obtaining a DC license.

If they don't, do they have any basis for obtaining it via courts or other means? 

Does anyone know if the successful buyer of a tax lien becomes responsible for back lot rent once they obtain the property deed?

Can anyone point me in the right directions as to where I can obtain public info regarding the integrity of the land.