I'm not that familiar with several of the countries discussed but can comment on others.
1. The Cayman Islands are heavily dependent on, and closely tied to, the US and its situation. The RE market and political arena there is in shambles and the Premier was recently arrested for corruption. and it's really, really expensive to live there as well as having very high requirements for emigrating there.
2. Costa Rica was once very attractive but has become quite dangerous because they do not have a national military. The drug cartels from Guatemala and Panama are taking advantage of that.
3. Panama has struggled since the US pullout of the canal region and has tried to develop tourism as a substitute.
4. The author left out Singapore.