I showed houses Christmas eve and took phone calls Christmas day. Nobody expects anybody to be working, they are off, and were surprised I was in the office (I work from home though and sometimes just come to the office to hide from the family).
The buyers are likely curious about listing after the holidays so keep in touch. The Buyers this time of year generaly are ready to go.
I find all the holidays to be rather busy for phone calls. BEfore I became an agent and my wife and I were looking for a home, we rode around on Easter Sunday looking at the neighbor hoods we liked. It fit our schedule, we called our agent with the info, knowing she was out of the office, and talked to her later.