Important: Mod is now a addon for UnifiedUI and not a compatch anymore
This means it can be used with and without polytheism reborn
It solves 99% of the issues of the faith window

The compatch only changes the gui for both sinews and polytheism reborn to work correctly
To be sure I updated the mod again with the latest gui file from both mods.

There is need for a compatch between Sinews, Polytheism Reborn and More tenets mod.
I will look into that.

As for the promote gaelic brythonic settlements decision it should only show when a neighboring
county is one of those faiths. As for now I can't reproduce the problems you encounter.
I would suggest joining the discord as it is a bit easier to help.

Oh and with this compatch on, I had the decision to create celtic empire (with some caveats : assyrian ??) available, and without it, it doesnt show, but I can take the decision to promote gaelic/brythonic/etc. settlements, which wasn't available with this compatch on.
Not 100% sur it come from the compatch, it may have to do with the reform/unreformed religion status

This compatch seems to mess with the UI of the religion tab when using both polytheism, more tenets and their compatch : when creating a religion with many tenets, it won't group them in order to fit in the religion interface but will spread them across the whole screen !
When disabling this compatch this is fixed