This is a good question, but one for which there isn't much of a satisfactory answer. I see two major reasons why historians are not writing books and articles on the topic: the limits of doing history on the Troubles and the relative invisibility of ethnic and non-Christian religious minorities in Northern Ireland.

The relatively recent occurrence of the Troubles means that some of the key records surrounding the events are still sealed. The deep ideological divides caused by this event also heavily influence the kinds of questions and answers that historians have pursued.

Moreover, there simply weren't many people of non-Christian religious minorities living in Northern Ireland during that era. The Northern Ireland census records have simply not asked explicitly about non-Christian religions. To take a few examples, during the Troubles in 1971, census records show .06% of the population was Jewish, .04% Hindu, .01% Muslim, and .004% Buddhist. In the first census after the Good Friday Agreement, .33% of Northern Ireland (just over 5,000 people) were reported as belonging to other non-Christian “religions and philosophies.”

Similarly for ethnic minorities, the populations were small and often overlooked. Censuses during the Troubles asked only about peoples’ birthplaces, not their races or ethnicities. The 2011 Census showed 98% percent of Northern Ireland was white, 1.1% Asian, 0.3% mixed, 0.2% black, and 0.1% other. This is a proportionally dramatic increase since the 2001 census, which listed over 99% of the population as white.

As for sources you might read, a little digging turned up a memoir by Tim Brannigan called, Where Are You Really From?: Kola Kubes and Gelignite, Secrets and Lies - The True Story of an Extraordinary Family. Brannigan was born to a born to a white woman having an affair with a Ghanaian doctor. Through some careful face-saving arrangements, his mother was able to adopt him from an orphanage and raise him as a part of her white family in 1960s Belfast. Far from being removed from the Troubles, Brannigan grew up in a republican family and faced imprisonment for possessing guns and explosives.

While you seem to have been thinking about non-white minorities, the largest group in Northern Ireland who felt themselves to be outside the Troubles was the Irish Traveller community. Irish Travellers are an ethnic minority in Ireland (with some members in the U.K. and U.S.), who are predominantly white Catholics. They identify as a separate ethnic group, and until recently, did not receive official government recognition. Known pejoratively as tinkers and gypsies, Irish Travellers face significant discrimination, hate crimes, and significantly poorer living standards. I haven’t been able to track down copies online, but the researcher and activist Dr. Robbie McVeigh has done oral histories and interviews with Irish Travellers, including on the question of the Troubles.