Regarding to tap of labor from the Caribbean,that will be for another research.After the ban on Indian Indentured Labor,Immigrants was sought from the coast of Africa.
1. British West Indian sugar DECLINED everywhere as it took time for the planters to adjust to having a paid work force and to having a work force which advocated for their rights.
In addition the UK no longer protected sugar from its colonies as it could have sourced it more cheaply from Brazil, Cuba as well as from beet sugar from Europe. Even Jamaica, then one of the world's largest sugarcane producers under went decline which led to the development of the banana industry. Labor shortages were NOT an issue on that island and in fact Jamaica was sourced as a labor source by US corporate interests who had projects in various Latin America nations.
2. There was NO attempt to source labor from Africa in the 20th century as such attempted HAD ALREADY FAILED. After slavery ended attempts were made to source labor from Sierra Leone. Africans were leery based on the fears of being enslaved. In fact the British were over taxing African subsistence farmers to force them to become laborers in the export crop sectors, which needed labor!
3. The planters sourced labor from the overcrowded Barbados as their plot was to have a divided labor force that they could exploit. Their apprehensions with Islanders is that they assimilated rapidly into the local black populations, and so weren't easily exploitable.
By the time the BGEIA advocated its attempt to turn the then British Guiana into a "colony" of India large numbers of Indian indentures had already been sourced. By then there was no evidence that BG had a labor shortage in its plantation sectors.
The point isn't about indentures bring brought to Guyana and Trinidad. The point was about the plot of the BGEIA to bring in people from India SOLELY FOR THE PURPOSE OF POLITICAL DOMINATION. The BGEIA lied about the conditions of indentures in Guyana in order to refute fears by India of abuse. They described BG as a paradise for Indians, which you know fully well was a LIE. But they did so to head off attempts by India to end that country as a source of indentures.