(Obviously) Milani for me. No religion like her's exists on earth so I couldn't claim it but the general outlook of Milanites (change, overthrowing tyranny, hope, etc.) very much fits in with mine. I have to imagine the church services are not unlike activist meetings. If not her, Cayden Cailiean or Desna; beer, dreams, and traveling are all things I like.
I like to go with the assumption that the world exists as it does not in spite of the presence of magic, but because of the presence of magic, and that some of the desert climes, for instance, would be completely uninhabitable without the existence of people able to magically create water.
Instead of asking the question, 'why is the world the way it is despite X,' the built in solution is to take it a step further back and assume that the world is the way it is *because* of X. Create water doesn't invalidate the existence of water-scarce desert cultures, it allows them to exist in areas so water-scarce that they wouldn't even exist without those magical resources, which also provides built in plot hooks, as village Y depends on their few adepts to keep the well topped off, and when a few of them are kidnapped in a gnoll raid, suddenly the entire village's survival hangs in the balance, as the town cistern keeps getting lower every day, and there is nobody to top it off (or not enough remaining adepts/clerics/whatever to keep up with demand)...
[I picked create water out of a hat, since it's been brought up before, but any of the other questions, like how plagues could exist in a world with remove disease, or how kings can die in a world where every kingdom has X people capable of raising the dead, can be dealt with similarly. Raise dead, in fact, is a *great* way to showcase how the world would develop / advance / progress much more slowly, since it's a sad scientific truism that for there to be any progress, the old generation, and their death-grip on their own theories, have to die off and make room for new thinking. In a world where the 'old generation' keeps coming back to hold onto the reins of power, and at the forefront of thought and philosophy, where the church doctrines are handed down from outsiders who *never change their minds,* no matter what their followers think of birth control or lady bishops, the world would be wildly more stagnant and traditionalist and resistant to change than our...
Additionally, I kinda of want to challenege that magic isn't saturated in society. I mean, I can think of several PFS scenarios where magic is used in the ways that people are saying it isn't (i.e. Hallways with Continual Flame cast on them, walls that clean themselves with permanent prestidigation spells, basins of unclean water with a wand of purify food and drink next to it). It seems to me like there is plenty of magic in society. I mean, would a ray of frost actually be a more cost effective solution than just getting a block of ice?
Well, I believe that all of Malebranche come from the Inferno by Dante, and the Archdevils are from the bible or texts like the Ars Goeta. Many of the names came from the 15th century, if not earlier, then were handed down in many occult texts. Of course, it's worth noting Asmodeus was also the name of the devil in DnD.
As for Demons, there's a difference in that it draws from other cultures the world over, as opposed to simply medieval Europe. Many come from classical Mediterranean or Celtic cultures, i.e. Orcus, while others come from the near East, like Lamashtu (who, I believe, was also a deity in DnD lore along with Pazazu). A similar theme run in the Empyreal Lords, although I believe a lot of more of them are made up.
The daemonic harbingers, on the other hand, I believe are mostly creations of Paizo. I don't know of any divine beings by names of the harbingers; by contrast, the names of the Horsemen are generally borrowed again from the bible or classical Greek/Roman sources. Additionally, while Szuriel (and Ragathiel) are not directly borrowed from biblical or Christian references, their names suggest that they are angels (as Michael, Raphael, etc).
There is a group of worshippers of Nethys who go around ensuring people are using magic correctly and helping those harmed by it...in order to ensure spellcasters continue to have a good name and that magic continue to be used on Golarion. I always thought that was a good backstory for an inquisitor who hated magic.