From a completely different angle - and not directly relevant to the OP but thoughts sparked by it.....

When I go to a dance club (in England) we dance various dances. Some are American Contra. Some from the 17th century 'English Dancing Master'. Some collected from the villages 100 yrs ago.
The style used for Playford is probably not as it was in C17, but it is distinct; dances from Northern England were danced with a rant step; modern Contra is full of added twirls.
Some like one style and use it for all the dances. Others would NEVER twirl in a Playford 'back to back' or California twirl in La Russe.
Evolution or blurring?