If we are going to talk about the early Proto-Protestants, aka Lollards, Hussites, and Waldensian, or others who became part of them, then maybe have a reform sosiety mechanism for them, where they can do multiple reforms, and when the reformation kicks off, they can choose between converting to the protestant or reformed faith without downsides, or just go their own way, and as a reward for surviving, having the reforms, they actually did, carry over as country modifiers.
The Thing with the early Proto-Protestants, is that they seemed to be railing against the fallings of the catholic church in their eyes, thus reforms, would make sense. Thus each reform, could use the disaster mechanism, or a variation of it, each reform, is a series of event, that deals with putting it into practice, with a reward at the end. Grant some of these some common ones, like local language bible project and local rites, which could simply grant, missionary strength or unrest, and curb church excesses, which either disables priestly estate or permanently lowers its influence depending on what makes sense for that faith, in addition to giving a money bonus, more taxes essentially. But each faith should propobly have some personal ones, that dont carry over to others. converting to Protestantism, should be an option, if they dont strike out on their own, which should not grant stability or prestige loss, since they are after all early Protestants, and acknowledges themselves as such, should not be penaslised, and such, a join the (convert to) Reformed or Protestant faith should simply have a requirement that center or reformation for that faith exist. Otherwise, they can do a strike out on their own reform, which grants them something else maybe? And disables converting to Reformed or Protestant free of charge. If you allow the catholic to crusade against heretics or atleast them up until the treaty of Westphalia, then you have an interesting game, of survival and rewards, with choice of striking out or joining the protestants. Granting the protestants a convertion bonus for these early faiths, where they are not primary faith of their state, could be a thing during the age of reformation to help, them disappear, as they historically did.
Propobly some repetition in there, but the mention of faiths without mechanisms, so well, here is one idea.
