Who and how to combine tax parcels in Dekalb County for a DSCR

[Nicholas LaGatta]

I have a property in Dekalb that was split into 2 tax parcels (main house and carriage house) or has possibly always been that way. I am looking to refinance, but I'm getting issues with potentially needing 2 separate loans. With the carriage house parcel, I'm getting an issue because the carriage house is only around 550 square feet and too small to qualify for my usual DSCR lender's standards.

My questions are the following: (1) What type of professional can facilitate the process of combining these parcels, including dealing with the survey, the city/county, etc.?  (2) Would this type of action likely to be successful given that we're currently legal non-conforming use, but not proposing any changes or improvements?  (3)  If combining the tax parcels is not practical, is there a specific lender than can refinance the 2 parcels under 1 loan, given legal non-conforming use?  

(Thank you in advance for not referring me to an REIA)