Not sure if I can address your opening questions, but I have done some work on my own Christian-themed D&D setting, actually stuck in ver 3.0 :rolleyes:
I switched Druids to “Forest Hermits”. Imagine a St-Francis-type out in the woods, dispensing cheerful wisdom to all who visit his humble hermitage – but woe betide anyone who tries to abuse God’s poor critters…! :eek: I got rid of the scimitar and some other things that seemed to make no sense to me, but you can tweak it as you see fit for your milieu.
I also brought back the Monk out of Oriental Adventures, making him a Friar Tuck type. Really good at fisticuffs and general beatdowns, generally not great with actual melee weapons, but very adept at using certain non-weapon items, actually as weapons: using an abbot’s crozier as a staff with trip capability; a thurible as a horseman’s flail; a candelabrum as a sai or jitte (depending on the number of sticks); a collection plate as a quoit; etc. Viking-type raiders have found, to their chagrin, that monasteries of certain orders can fight without penalty with almost anything in their monastery as an efficient weapon. I had such a monk character in a campaign I was in years ago: Brother Sebastian, of the Abbey of St Martin the Thrice-Martyred. He looked like a cross between JS Bach and Leo McKern.
Another thing to look into may be the early Deryni books by Katherine Kurtz. Takes place in a medieval Christian world, but not of this Earth. (Her later stuff seems to have gotten more Gnostic, and I believe she is since “ordained” a bishop in the Celtic Catholic Church. Caveat lector.)
I have an order of pseudo-Templars, called the Pandectine Knights. Like the Templars the have three parts, the Chaplains (clerics), Knights (paladins), and Serjeants (fighters). Chaplains generally use maces, steel-shod staves, etc, and eschew edged or pointed weapons, because of the old “rule” about not drawing blood. (The fine print in canon law, however, maintains that law only in fighting living humans. Against non-humans and the undead, all bets – and restrictions – are off.)
I also had clerical abilities granted by the Church. Clerics are all ordained priests. If a cleric is elevated to the office/rank of Metropolitan (or Abbott for cloistered clerics), he can ordain another cleric (thus granting clerical powers). Once he reached the office/rank of Atriarch (or Archimandrite), he can elevate a cleric to the Metropolis/Abbacy. Also, priests can forgive/retain sins, command minor quests, lift minor curses, etc. Metropolitans can excommunicate (with various details and effects I haven’t quite worked out). Atriarchs can anathematize (ditto).
Monks and clerics have the feat Chant, which allows a group of said characters to gather together and start a holy chanting, which they can use to bolster the power of another cleric’s “spell” or other effect trying to be accomplished.
Oh, and regardless of character class, feats, or skills – or lack thereof – the **rightful **King of any country, crowned or not, can cure scrofula by touch and can, one day per year, stick a sword in a rock and pull it out again as many times as he wants.