What crewed charter company are you with? They should be able to provide a lot of help.

Some crewed charter boats offer diving and at least one crew member is a dive master or instructor. If so, they can help with dive sites. BVI has a lot of dive sites. Selection of dive sites is weather dependent.

There are a lot of choices of duffle bags with frames and wheels. You likely need a bag that does not take up a lot of storage space on board the boat.

Are the costs of clearing into the bvi included?

Warren S/V Scuba Doo
Lagoon 50 (winner of best crewed yacht under 55 feet at the St. Thomas crewed yacht boat show).

https://www.cyabrochure.com/ebn/2307/pdyrX/6642/4///