How then do you explain the complete and utter failure of the Protestant Dutch colonies and the expansive reliance on the institution of slavery in the predominant Protestant regions and colonies?
The Dutch never settled in Central and South America as much as other European nations did. The Dutch had greater success in Asia.
But even with that being the case, Suriname did not gain independence until 1975. The Netherlands Antilles and Aruba are still today part of the Netherlands.
As for slavery, Catholic colonies relied heavily on slavery when the native population was not sufficient for their labor needs. Perhaps you have heard of the slave revolt in Haiti under the rule of Catholic France, the great beneficiary of the Natural Law.