I think that it might be a little easier for Canadians to immigrate and find work on British Islands like the Caymans and T&Cs because they are all part of the British Commonwealth, I've met a lot of Canadians living and working there - but that's just a guess.
I've also met many folks working in the Caymans that are unhappy about the "work permit term limit" for foreign workers, see below. They can't get work permtis for longer than 7 years and they can't apply for permanent residency until they have lived there for eight years.
So they find a job, get established and then have to leave for 2 years and start over. During our last trip we were speaking with a bar tender from the US who said that she had previously worked as a Dive Master for Red Sail on Grand Cayman, but had to leave when her work permit expired. She was eager to return to Cayman and managed to find a bartending job when she was eligible to return.
If I were to retire to someplace warm with tropical diving it would probably be in the US, like Florida (or Hawaii - if only I could afford it!) or one of the US Caribbean Islands, so I wouldn't have to worry about immigration and healthcare and work permits.
I remember sitting at the bar at the Cayman Brac Beach Resort a few years ago and talking with the dive shop manager, I can't remember his name at the moment, but he told me that he would soon have to leave because his work permit would expire. A few year later he was back in Cayman as the general manager for the Little Cayman Beach Resort and I seem to recall hearing that he and the dive shop manager (Sharon) had gotten married. I remember that Sharon was from South Africa and I think that she mentioned that she was now a Caymanian Citizen. So it sounds like they have found their place and will likely remain in Cayman for a long time - I am glad because they are good, hard-working people and deserve to be happy.
One day when we were out and about on the island of Cayman Brac a couple of years ago we bumped into Barb, the popular divemaster at Cayman Brac Beach Resort, and she introduced us to her daughter and husband. He was was born in Cayman and works in the local fishing industry. Barb said she was originally from Canada but has been happily settled in the Caymans for years, so they are more nice people that have found the best place for them.
So living and diving on a tropical island is not an impossible dream, but I don't think that it is very easy to arrange.
Term limit
Seven years is the maximum length of time a work permit holder can work continuously in the Cayman Islands. After this period the board cannot normally grant the person any further work permits until he or she has left the Islands for at least two years. The only exceptions to this would be a worker designated as an 'exempted employee' in a business staffing plan, or where the board considers that there are exceptional circumstances. In such cases the board may, at its discretion, grant additional work permits to enable the person to complete an aggregate period of eight years, thus making him eligible to apply for the grant of permanent residence.