[rootos]

Fiji and Mauritius sound great for you, as do Trinidad and Tobago

French Polynesia (English probs though)

Dominican Republic is easiest for Visa

British dependencies/territories in the Caribbean?

You could get an answer by doing some basic research...

[akmarinov]

These are all great for the chill, exotic, beach going part, but considering OP has a 6 month son - things like kindergarten and schools are, let's say, subpar in all of these places.

I'd go with Australia or New Zealand that I think gets you the best of both worlds.