The main religion of the land- more so in the East than the west- is of the God Amadan, a faith carried with the human settlers when they first came to these lands. Allegedly he cam down to the world himself and guided his followers from the northlands (which for some reason had become uninhabitable due to climate, dragons, invasions, etc.) to the sunnier havens down south. Even still, there were other forces there at first, and things started off pretty barbaric. Allegedly, a mysterious traveller who glowed slightly often toured between the tribes, offering wisdom and settling disputes. After things settled down some, people realized they didn't see the mysterious traveller anymore, and started to write down as much of his judgements as possible, assuming that if this was not Amadan himself, it must have been a successor prophet. Most of the teachings of the Church of Amadan come from tales of these early days... and of course, there is some debate over which records are the most accurate. There are some claimed accounts of the prophet that are rather, um, weird- later dismissed by the church as made up by jealous communities who hadn't been visisted by the prophet. So they were declared apocraphyl and buried. Speaking of which, the church's hiearchy is based out of the city of Belaluna, on the coast. As a practical matter, the church has some generic (by our standards) teachings on love & helping others, but a bit more focus on "justice" and even vengeance than most modern ones. Many devout followers of Amadan are also judges or town guardsmen. Amadan, of course, is the One God and while he may have little servant helpers, and some demonic enemies in the world Beyond, he is still the only one truly worthy of being called a God.
So, with the existence of clerical spells, why doesn't everyone embrace Amadan? Simply because there's stil some debate about where clerical spells come from. Some devout followers of Amadan have been completely unable to cast a spell, no matter how hard they tried; more importantly, people who claim to not give a whit over Amadan have managed to cast clerical spells succesfully, and found their own schools. They claim that these spells are merely a different school of magic that requires less arm movement.
While the church of Amadan is more prevalent on the Eastern coast, it's still generally accepted in the west (the lands of old Meria), even if there aren't quite as many shrines littering the landscape. Belief in other gods is generally rare. Some of the human settlers who first came to Greater Meria intermixed with the previous inhabitants of the land (the elves? Or perhaps similar folk?) and adopted the worship of some of their deities. Fear of these nuts sacrificing good Amadian children generally drove this pagan worship underground, though. The most notable place where it survives is among some groups of Druids- notably in the Sumpfe Marshes, but in other random spots as well. Not that there aren't Druids who cheerfully worship Amadan, a god more associated with cities. When there's only one God, it becomes easy for people to see it as they want to, you know...
Among non-humans, the few remaining surface dwarves have adopted Amadan worship, and most halflings lazily acknowledge it (while very few actually join the priesthood). The elves, goblins, & orcs all have their own respective "old" pantheons, generally listening to them.
Also of note lately is the movement called "The Fire Blades." Most clerical spell-casters tend to spend their time making money as doctor's clinics, with a few being advisors to important people or serving as combat medics in times of war. The Fire Blades- often using the spell "Flame Blade," I might add- puruse a rather more aggressive approach to clerical spells, and have offered their services to various barons & powers.
Undead are considered fairly rare. You'll most likely only know specific knowledge on them if you went to a mage school, where necromancy is not taught anymore but it is known to exist in reference and history books. Peasants on the ground still have tell tales of ghosts & spirits- you know, generic haunting style stuff. However, few know about mages or clerics who can make "zombies" rise from the graveyard on command.
Resurrection is practically unheard of. If you're dead, you're dead. Only the greatest miracle will bring someone back to life- think a 10th level Cleric spell. Yes, that means you can ignore Raise Dead, Ressurection, etc.
With respect to spell lists: I forgot to mention one, rather important change. Diviners can be thrilled, being that the spell Scrying, in this world, is 3rd level rather than 4th. A bit easier to do. On the downside, the spell Nondetection is now 1st level. It works pretty much as described in the PHB, with the addition being that the DC increases by 1 for every mile in distance. So it might still be possible to use Clairaudience to overhear a conversation in the backrooms of a bar while out front and breach the ward, but you will not be able to spy on all your enemies from the castle. There is also a 2nd level spell, "Area Nondetection," that functions like an enlarged version... instead of warding everything with 30 feet or so of the target, it's more like 500 feet.
What this means in setting terms is that permenant versions of these spells are often set in magic items- rings, pendants, etc.- and are used all the time by people, especially wizards. If anything, succesful scrying on a person often raises suspicion that they WANTED others to hear whatever happened during the lapse in protection. It is rumored that archmages have a way of breaching these wards, but even that involves special preparation and sympathetic items.
As a side note, the slightly easier availability of Scrying does make for an interesting communication tool, but as people found out rapidly, only for messages you don't mind being made public, since others can easily scry them out too.
Scrolls: Scrolls are more expensive than listed as in the PHB. Higher level-scrolls cost the same, but the level-1 stuff isn't so sillily easy to get. Yes, this is mostly due to metagame worries of booting the Wizards and replacing them with Rogues with a high "Use Magic Item" skill, but also just to make spells prepared by Wizards more relevant.