Thank you for your response, Carl. I have not contacted Chris as of yet. I did, however contact Jay Coke, formerly of the Summerville Museum, who unfortunately had few answers for me. Summerville is abounding with odd homes and properties though apparently little records were kept on servant homes.
Although there were surely many more homes at one time in Summerville such as mine, with two front doors, there are now only four. I feel blessed to have discovered and uncovered such a rarity. It is truly a shame that the structures of centuries past are being destroyed.