Some twists and turns in this thread for sure!
The one pvp server (sullon?) back in the day split the playerbase into evil-neutral-good based on deity. It was a division of convience rather than pure lore or logic, but a worthy attempt in my view of attempting to get players to cooperate along "faction" lines.
Aside from Veeshan, whom I suppose is neutral (and arguably is irrelevant as was only a deity choice for non-bards with the super-later addition of Drakkin... the only single deity race that has paladins and sk sharing faith as it were) there was some trends in original design?
1. Clerics, shaman had to have a deity. Civilized races got clerics, tribal got shaman (until froglok broke that rule)
2. Paladins, druids and rangers were good deity, Shadowknights and necromancers were evil
3. Wizards, Magicians and Enchanters had wide diety choice, as do bards (bards have unique ones)... agnostic being a useful option for questing, but the least daring choice as far as in-game consequences
4. agnostic was limited to warrior, monk, int casters and bard (before Vah Shir and Berserkers were added, agnositic berserkers being very odd in the deity slate of some races such as Troll that were very focused on Cazic or Inny)
5. rogues were evil, bristlebane playful (neutral) or "scouts" of a good god (wood elf)
6. pretty much every (or maybe all) warrior race can be a follower of Rallos Zek (except the later-added races) despite that not being an optional deity for most races for any other of their class options.
7. Iksar as the first added race were all Cazic Thule.
Basically, Deity had as much to do with class choice (if not more than race). If a bunch of halflings decide to go slumming with barbarians, we should expect: new facial tattoos on halflings, shaman, beastlord added as classes with The Tribunal/Bristlebane being the logical deity choices.
Racially Iksars are smart enough to be int casters but not wizards. Erudites of Paineel are lore-wise brilliant. No wizards. Cazic Thule is anti-wizard!
Other factions liked or disliked you based on your race, deity and class. Agnostic human monks are okay in the "evil" outpost in overthere because although monk is probably not a loved class there, agnostic and human are both neutral or at least tolerated (in the case of human).
Frogloks discovered hate, Inny became a deity choice and rogues, Sk and necro (and inny clerics) were opened up as class options. As others mentioned, halflings got additions without it even being explained. Gnome had bertox vs. brell split in Ak Anon in place before gaining other classes.
NPC races mish-mash most of the "class rules" as they have tribal races such as the Sarnaks with int casters (sarnak have a great class range actually). Orcs, kobolds, goblins in old world alone have a wide variety of classes that make them "smarter" than quite a few of the playable races... and aren't most of them followers of Rallos? (at least in historic lore?).
Would a Drakkin ranger train a dark elf of whatever deity to be a ranger? Lorewise... absolutely, but that's leaning on the weakest "muppet family we all get along" lore in the game. If Errolissi (spelling) or Bristlebane went nutty on Norrath you could give anyone "good" class or "goofy" class choices within lore easily.
High elves are the selfish elite of Norrath, that is a slippery slope to evil. Just add "Discord" as a deity choice and have Felwithe betray the rest of Norrath... so many ways to forward storyline and give us more things to play.