Some of the religion flavour names are pretty janky, so here's my suggestions for improvement and a 00_religions.txt with the changes if you like the look of them.
JUDAISM
The scripture name for mainstream Judaism should be "The Tanakh" rather than "The Torah", as the canon beyond the Torah had been settled by Crusader Kings II's timeframe. If you're confused: The Torah is just the first five books of the Tanakh (Genesis, Exodus, Leviticus, Numbers, Deuteronomy) while the Tanakh also includes the books of the prophets and other writings.
Judaism's two heresies, Samaritan and Karaite, should retain "The Torah" since they rejected the rest of the Tanakh.
Although the current use of "Satan" for Judaism's "evil god" name is misleading, it's probably the most appropriate as it is sometimes used to refer to the Yetzer Hara (evil inclination) of man, though rabbinic Jews didn't and don't believe in a personification of evil. Perhaps Lilith could be added, since she was a popularly known wicked entity in both Rabbinic and less orthodox Judaism.
CATHAR
I'd add "The Demiurge" as an evil god name due to the Cathars' alleged gnostic theology.
ZOROASTRIANISM
I'd change the scripture name from "The Gathas" to "The Avesta". The Gathas are held in a primary position by academics who study Zoroastrianism, not by Zoroastrians themselves, for whom they are just a part of the The Avesta.
HINDUISM
Probably has the worst flavour text. Using "Brahma" as the high god name is highly misleading, the god Brahma was hardly worshipped as an independent deity. Perhaps Paradox meant Brahman (often becomes "Brahma" when inflected) which means supreme reality or God, but in that case they're just being confusing to English-language players. I'd propose "Ishvara" (The Lord) as the high god name, since it means the supreme, personal, God of devotional Hinduism. The player will be a Hindu noble rather than a priest or philosopher so it makes sense to reflect popular beliefs rather than high theology.
Also, Vishnu and The Goddess should be added to the lower god names.
"The Vinayakas" as the only "evil god" name is bizarre. The Vinayakas are pretty ambivalent (as far as demons go) and are of minor importance. Vinayakas should be removed and replaced with "The Asuras" (anti-gods) and "The Rakshasas" (evil spirits). Also, the use of "Kali worship" for demon worshippers is highly misleading. No doubt Paradox mean Kali (with a short 'a') which is a personification of the low moral character of the current world age. But since the game text doesn't use diacritics in Indian names, it appears idential to Kāli (with a long 'a'), a goddess who you can worship as a non-demoniac in the game. I'd suggest the broader and more appropriate "Asura worship".
Although "The Mahabharata" as a scripture name is appropriate, it's far too narrow as there are a huge plethora of Hindu scriptures that would appeal to a medieval Indian noble. At the very least I'd change it to "The Itihasas" which means both the Mahabharata and the Ramayana (the other popular Hindu epic). I'd also add "The Puranas" which are popular compendia of religious stories, rituals, and moral instructions; but I'm not sure if the game allows multiple scripture names.
BUDDHISM
Due to the huge variety of Buddhist thought I think Paradox gets some leeway here. "Brahma" is acceptible as the high god name, since Brahma is the nearest Buddhism gets to a top god, although of course they don't believe in a supreme deity and an elightened being might be greater than Brahma.
Of the lower god names, the only changes I'd make would be changing "The Arhat" to "The Arhats" and adding "The Buddhas" to represent the multiple past and celestial buddhas which were and are venerated. The current "Perfected Ones" is too generic.
I'd add "The Hungry Ghosts" to the evil gods, as it's the standard English translation of Buddhist concepts of malevolent departed spirits.
JAINISM
For the high god name, "Paramatman" (the supreme self) would be more appropriate than the current "Tirthankaras". Paramatman is the closest Jain concept to God, Jains believe that every soul has the potential to become Paramatman by being purified of all karma, and it is worshipped in its own right. I'd move the Tirthankaras to the lower gods and add "Mahavira" who REALLY should be on there as the latest and best known of the Tirthankaras.
As for the evil god names, I don't know where "The Punishers" comes from. Instead I'd add "The Asuras" (meaning demons, as with Hindus), and "The Ghosts" to represent Jain belief in malevolent departed spirits, similarly to Buddhism.
I'd change the scripture name to simply "The Sutras". The core Jain texts are collectively called the Jain Sutras in English, trying to find a more specific name would be artificial in my opinion.
JUDAISM
The scripture name for mainstream Judaism should be "The Tanakh" rather than "The Torah", as the canon beyond the Torah had been settled by Crusader Kings II's timeframe. If you're confused: The Torah is just the first five books of the Tanakh (Genesis, Exodus, Leviticus, Numbers, Deuteronomy) while the Tanakh also includes the books of the prophets and other writings.
Judaism's two heresies, Samaritan and Karaite, should retain "The Torah" since they rejected the rest of the Tanakh.
Although the current use of "Satan" for Judaism's "evil god" name is misleading, it's probably the most appropriate as it is sometimes used to refer to the Yetzer Hara (evil inclination) of man, though rabbinic Jews didn't and don't believe in a personification of evil. Perhaps Lilith could be added, since she was a popularly known wicked entity in both Rabbinic and less orthodox Judaism.
CATHAR
I'd add "The Demiurge" as an evil god name due to the Cathars' alleged gnostic theology.
ZOROASTRIANISM
I'd change the scripture name from "The Gathas" to "The Avesta". The Gathas are held in a primary position by academics who study Zoroastrianism, not by Zoroastrians themselves, for whom they are just a part of the The Avesta.
HINDUISM
Probably has the worst flavour text. Using "Brahma" as the high god name is highly misleading, the god Brahma was hardly worshipped as an independent deity. Perhaps Paradox meant Brahman (often becomes "Brahma" when inflected) which means supreme reality or God, but in that case they're just being confusing to English-language players. I'd propose "Ishvara" (The Lord) as the high god name, since it means the supreme, personal, God of devotional Hinduism. The player will be a Hindu noble rather than a priest or philosopher so it makes sense to reflect popular beliefs rather than high theology.
Also, Vishnu and The Goddess should be added to the lower god names.
"The Vinayakas" as the only "evil god" name is bizarre. The Vinayakas are pretty ambivalent (as far as demons go) and are of minor importance. Vinayakas should be removed and replaced with "The Asuras" (anti-gods) and "The Rakshasas" (evil spirits). Also, the use of "Kali worship" for demon worshippers is highly misleading. No doubt Paradox mean Kali (with a short 'a') which is a personification of the low moral character of the current world age. But since the game text doesn't use diacritics in Indian names, it appears idential to Kāli (with a long 'a'), a goddess who you can worship as a non-demoniac in the game. I'd suggest the broader and more appropriate "Asura worship".
Although "The Mahabharata" as a scripture name is appropriate, it's far too narrow as there are a huge plethora of Hindu scriptures that would appeal to a medieval Indian noble. At the very least I'd change it to "The Itihasas" which means both the Mahabharata and the Ramayana (the other popular Hindu epic). I'd also add "The Puranas" which are popular compendia of religious stories, rituals, and moral instructions; but I'm not sure if the game allows multiple scripture names.
BUDDHISM
Due to the huge variety of Buddhist thought I think Paradox gets some leeway here. "Brahma" is acceptible as the high god name, since Brahma is the nearest Buddhism gets to a top god, although of course they don't believe in a supreme deity and an elightened being might be greater than Brahma.
Of the lower god names, the only changes I'd make would be changing "The Arhat" to "The Arhats" and adding "The Buddhas" to represent the multiple past and celestial buddhas which were and are venerated. The current "Perfected Ones" is too generic.
I'd add "The Hungry Ghosts" to the evil gods, as it's the standard English translation of Buddhist concepts of malevolent departed spirits.
JAINISM
For the high god name, "Paramatman" (the supreme self) would be more appropriate than the current "Tirthankaras". Paramatman is the closest Jain concept to God, Jains believe that every soul has the potential to become Paramatman by being purified of all karma, and it is worshipped in its own right. I'd move the Tirthankaras to the lower gods and add "Mahavira" who REALLY should be on there as the latest and best known of the Tirthankaras.
As for the evil god names, I don't know where "The Punishers" comes from. Instead I'd add "The Asuras" (meaning demons, as with Hindus), and "The Ghosts" to represent Jain belief in malevolent departed spirits, similarly to Buddhism.
I'd change the scripture name to simply "The Sutras". The core Jain texts are collectively called the Jain Sutras in English, trying to find a more specific name would be artificial in my opinion.