How can I use my Caribbean citizenship to apply for the EB-5 visa after renouncing my original nationality?

It sounds like you are seeking to apply for your eventual immigrant visa processing at an embassy other than in China. This may be achieved based on where an immigrant legally resides overseas. You should consult with an immigration specialist to take steps to begin your EB-5 processing.

You can apply now as it does not matter what nationality you have. You can always update the record later with your new passport; many applicants have more than one nationality and place of birth is what matters for visa allocation.

Green cards are based on country of birth so the Caribbean nationality will not help for EB-5 but would allow you to apply for an E-2.

Your country of birth will control when an immigrant visa becomes available to you to consular process or adjust status if you are in another lawful nonimmigrant status in the US. If you have a spouse who is from a different country than your country of birth, you may cross charge to your spouse''s country of birth. You will be required to disclose all current and previously held nationalities in your DS-260 or I-485.

Yes, you will disclose all current and previous citizenships on the application.

You will have to list all countries that you are or have been a citizen of during the EB-5 process (during consular processing or adjustment of status). Your country of birth will control when you are eligible to receive a visa based on annual quotas. You can pursue the process before you renounce one nationality or after the process has been completed.