This has no effect on the Christian saintly bloodlines. This will work on old saves and will work in ironman, though it will disable achievements.
So far this has been working exactly as I wanted it to in my campaign, let me know if you run into any bugs! So for example, a Norse defender of the faith gives a small boost to heavy infantry, whereas a Zun defender of the faith gives a small bonus to movement and siege. The 'Defender of the Faith' bloodline now gives a toned down version of that faith's special combat leader trait. The bloodline that previously gave +15 to Jewish folks now gives +3 to all non-pagans. I also made a small change to the bonus given by two of the previously broken and inaccessible bloodlines:
So I opened it all up! Each ancestor bloodline can be unlocked by every pagan faith, though some faiths will have an easier time than others depending on the specific bloodline and other doctrines you take. Leaving just the one that gives great warriors. The problem is half of the bloodlines are broken and don't get called correctly by the event half of the remaining bloodlines are restricted to certain government types, mostly Tengri nomads and 3 of the last 4 have super rare conditions. But others came and brought ruin to these cities, taking their people in chains to this continent in his anger God struck down the Old World. In a vanilla game you will pretty much only ever see 1 ancestor veneration bloodline, unless you're playing Tengri Nomads in which case you'll see 3. Stories told of a time before The Fall, when the Ancestors of all these people were one of the Lost Tribes of Judah- Israel, builders of great cities of gold and salt in lands far across the ocean.