First off I would extend your trip to at the very least 7 days. But if that isn't an option here is my suggestion.
Arrival Day: have the majority of your provisioning delivered and provision the rest the day you arrive so you can get off the dock early the next morning.
Day 1. Nanny Cay -> Scrub (have friends meet you there or you could take the boat to Trellis to meet friends and then go over to Scrub...personally I would play it by ear based on if their flight is on time. Make sure to snorkel Diamond Reef (off Great Camanoe between Scrub and Marina Cay). In my opinion this is one of the best snorkeling spots in the BVI right now.
Day 2. Scrub-> The Baths -> North Sound (you could even stop over at the Dogs to snorkel if you want)
Day 3. North Sound-> Monkey Point (Snorkel) -> Cane Garden Bay or Diamond Cay
Day 4. Cane Garden or Diamond Cay -> Great Harbor Jost; White Bay (since you have a captain, I would take the boat to White Bay during the day and then have the captain take it back over to Great Harbor for the night so you can go out to eat and check out Foxy's. We love Corsairs but there are lots of good dinner choices in Great Harbor.
Day 5. JVD -> Norman Island; (snorkel the Indians, lunch at Willy T, caves at Treasure point, dinner at Pirates Bight)
Day 6. Return to Nanny Cay
I do like Cooper so might do that after Scrub, instead of Cane Garden or Diamond Cay. There is pretty good snorkeling at Cooper off Cistern Point. I would not try to snorkel the Wreck of the Rhone. It is more a dive spot and there are so many better places to snorkel to actually see stuff.
Enjoy!