For a fee, you can schedule a personal trainer at the Ship Shape Health Club and Spa at the BC/YC. Not sure if any other resorts offer the same. I have not heard of any type of yoga class.
I few years back, while staying at the Beach club for the Januaray marathon, there was a yoga class held on the sand in front the BC/YC at least once a week, now thinking it was at more often...probably at least twice/week. It was early, seems like it was just after daybreak, and it was wonderful. Sometimes chilly, but during our stay we had mild weather for the most part so enjoying the morning sun coming up while looking at the beautiful Boardwalk area was very special.
Wish they would have that again. Maybe they will someday.