Unfortunately, you are not eligible for a second citizenship in any of the Caribbean CBI countries, including Saint Lucia, if you have an issue getting a Schengen visa. If you apply and don’t have the issue rectified, your application would be declined.
Ask A Question | Learn more about Saint Lucia
How can I apply for St Lucia citizenship with history of visa overstay?
When I was a teenager (13 years ago) I once overstayed my visa in the EU by 20 days and it was put in my record. I have been unable to get a Schengen Visa after that but I did get multiple US tourist visas (never overstayed). Would I qualify for a St Lucia golden passport with this on my record?