Another part missed: Georgia, North Carolina, etc all have quite liberal colleges that skew the 18-24 vote to the left also.
Georgia-Its trending Dem because of Black Northeastern Transplants moving into the state most notably Atlanta and its suburbs but the Atlanta Suburbs more so.
North Carolina-Yeah "The Research Triangle" which contains universities Duke, UNC, NC State, and Wake Forest are trending the state Dem. Also, the city of Charlotte is pretty Dem per info from Wikipedia because South Central, Eastern(I guess Northeastern), and Northern areas of the city are Dem. The only part of Charlotte that is Republican is the southeastern part of the city.
Not to nitpick, but Wake is in Winston-Salem, which is nowhere near the Triangle. Also, Charlotte is a financial center, and finance is a lean Democrat industry.