I'm thinking of taking a small group there, but some of the group are snorkelers....what is available to them?
How about non-diving, non-snorkeling spouses?
There isn't any snorkeling at the CBBR property. There is a beach but there is boat traffic and turtle grass. There is an amazingly beautiful infinity pool and lovely places to relax in a hammock or on a lounge chair. I have met non-diving spouses there and they said they loved the pool and the quiet relaxation.
There is also a small spa at the resort that offers a good range of services, and every night the resort hosts entertainments and games, and there is a small gym. There is also a tennis court if anyone in the group likes to play tennis.
I have never tried snorkeling on Brac but I know that the Cayman government has recently installed signs and ladders/entries for shore diving and snorkeling at various locations around the island - perhaps others can tell you about snorkeling Brac away from the resort.
There's a lot of natural beauty to enjoy, the cliff, fishing, kayaking, bird watching, hiking, climbing, and caving - and the resort provides loaner bicycles at no charge. There's a lovely wetland and nature preserve across the road from the resort with a few benches and picnic tables and it is very pretty.
So it is a beautiful and relaxing place, and a nice resort and the food is excellent for buffet style, but there are not a lot of tourist activities. There is a small museum that is worth a visit.
Here are a some links about Brac:
http://caribjournal.com/2015/09/15/journey-to-cayman-brac/
Cayman Brac video:
https://vimeo.com/165357805
https://youtu.be/NTcZso-Zg80
Cayman Brac free tours:
http://www.islands.com/free-tour-you-cant-miss-cayman-brac
Shore Diving Brac:
Shore diving on Cayman Brac?
https://www.scubaboard.com/community/posts/8137929/
https://www.xray-mag.com/pdfs/articles/Travel_CaymanBrac_LawsonWood_60_locked.pdf
This charming movie called "Cayman Went" (streaming online) was filmed on Brac and you get to see a lot of scenes of the island above and below the water:
https://vimeo.com/104722556