What is the status of major religions in the BT universe anyway?
Except St Blake, of course, may his HPGs light your path.
Pretty much the way they are today (I mean in the today of the 80s when the game came out).
Federated Suns and Lyran Commonwealth are space British and space Germans respectively (they even use pounds and kroners as their currency; C-Bills are Comstar currency). Christianity is massive in those states. The ruling houses are outright stated to be Catholics (FedSun being an offshoot of the Catholic faith while LC is the original Catholics).
Draconis Combine is basically a combination of Shinto and Buddhism, more or less, being space Japanese.
Capallen Confederation, the space Chinese, is definitely Buddhist.
Free Worlds League is Christian of some sort, with strong influences from the Romance era of chivalry and the like. They are supposed to be an amalgamation of Greek and Italian cultures.
The Clans are generally atheists. They revere the past and their ancestors, although some dabble in animism and vision quests a la Native Americans.
Islam didn't get off Earth until late due to them not wanting to lose track of where Mecca is. Trying to figure where to bow to sniff the ass of the guy in front is difficult when the direction is basically "another planet". When they eventually did, they never made it as a coherent entity and settled a few planets in the Al Nair region in what eventually became the Draconis Combine. A small group made it all the way to the Periphery past the Bandit Kingdoms and started a war with the Spanish already settled there (Umayyad Caliphate vs Neuva Castile). Those that stayed on Earth didn't make it past ComStar's invasion of Earth after Kerensky's Exodus, although they might have already been wiped out by Amaris beforehand.
Hindus are scattered as well. The Thugee branch of the faith have a stronghold in the Capallen Confed due to Romano being viewed as a Kali avatar and she in turn protecting them and using them as her personal assassins. There are also presumably groups in the Draconis Combine, with the head of the ISF (Subhash Indrahar) being a possible one (it isn't explicitly stated that he is, but it was mentioned that he had a "Hindi background", which might refer to his ethnicity rather than religion, given how obviously fucking confused Stackpole was with regards to that topic).
These are the main groups. BTech, being a "everyone is brown" kind of setting, basically said that there is a bit of everything in every "nation" or group, although how you can have lone muslims running around a sea of Christians is rather unexplained. He must have spontaneously turned to a religion that he had never heard of in his life. Truly, divine intervention was involved.