Today I went searching for more information about what exactly this was, as I only had a few moments to take my photos and get on with my day. Here is what I found out -- this event has been taking place at the Witch House for about 8 years now. These cool folks are Colonial re-enactors whose period dates from the 18th century, so while not exactly the period of the Witch House, this is nonetheless fun to see from a "Heritage" perspective.
I spoke to Elizabeth who is the Director of the Witch House, and she said they don't heavily advertise this event as the Witch House already has a big draw, and they don't want to overwhelm the place.
If you are planning to come to Heritage Days in 2015, this is something to put on your agenda as a "not to miss" event, at least in my opinion. The dates of Heritage Days next year are August 1 - 9, and this event, if held on the "same" weekend would be on Saturday, August 8, 2015.
I hope to see you here.