Similar to language generation I think we'd want to start out with;
creation myth
deities, or beings of similar power
personas, outlooks & whatnot of said beings
base myth(s), including creation ideally and where beings or sub-sets of them come from / interactions between them
from there we can split into religions, where religions take & mutate the above into their own spin, splitting some beings, renaming, ignoring others, flipping the perceptions / stories a bit (ie. a "sinister" being in religion A might be considered more neutral or a "testing" deity in religion B, with the myths slightly bent, added to or removed from in order to fit the narative)
The next step then is deciding tenants, teachings, rituals and so forth from the beings the religions follows most closely (or ..fears most I guess).
Some form of mutation mechanism for the stories / tenants / teachings might be appropriate, similar to how language might mutate as cultures merge, time passes etc. I envision this being similar in spirit but for oral / written / tradition targets instead.
Similar to language generation I think we'd want to start out with;
The next step then is deciding tenants, teachings, rituals and so forth from the beings the religions follows most closely (or ..fears most I guess).
Some form of mutation mechanism for the stories / tenants / teachings might be appropriate, similar to how language might mutate as cultures merge, time passes etc. I envision this being similar in spirit but for oral / written / tradition targets instead.