Finding a surveyor might be a bit difficult in the Caribbean, unfortunately. *DO NOT ask the seller to suggest one, though. *The insurance company you go with would be a better source of information about a surveyor they trust.
For gear, Budget Marine is very good. *We started buying from Robbie Ferron more than twenty years ago when he operated out of a ship's container in a driveway in Philipsburg. *It's a much different operation nowadays, but exceptionally convenient, with stores in St. Thomas (USVI), Antgua, St. Maarten, Grenada, Trinidad, Bonaire and Curacao. If you are from the US and want to bring things in from the States, then you would want the boat in the USVIs (NOT the British Virgin Islands or duty would be charged) or Sint Maarten/St. Martin, a duty-free island. *Since Budget Marine has an online catalog, you can price compare before you think about lugging stuff from the States, however.
If the boat is French, you might need French gear (turnbuckles is one item that we found on our French boat could not be obtained elsewhere - different threads, etc.). *Then Guadeloupe, Point-a-Pitre is the place to look - there are a few chandleries there, though I can't remember much about them anymore. *Only place where we could get parts for our Eno stove, though. *Very expensive!
St. Martin can handle hauling a catamaran in various yards. *Maybe Kirk on Gallivanters will check in here and give some advice about the VIs. *Grenada is another option, but I'm not up to date on yards there.
Curacao in many ways is an excellent place to go, but..... once there, returning to the Eastern Caribbean is a lot of hard work.