Will they flourish in Southern coastal South Carolina?
I could not find moon vine on the list of salt-tolerant plants. It is perennial in zones 10-11 and grown as an annual north of this. It is in the morning glory family and self-sows freely - some would say to a nuisance level. Here are good resources for you. http://www.clemson.edu/extension/hgic/plants/pdf/hgic1730.pdf