I was thinking about two more NPCs:
An old drunk who you could give potions of vodka to. He would have an extensive list for chatting, various cryptic rumors about game mechanics and secret stuff. This way, even non-spoiled player without the wiki would have a way of learning about some of the more obscure stuff. For example, he could say:
Once I ate a resurrected banana and gosh, was it tasty!
I met an angel once. He fixed my arm.
Don't eat too much, my mama told me, or you'll grow fat and clumsy.
I heard that unicorns taste weird. Not that I would know first-hand.
Tweraif? Yeah, I heard about it from a guy... What was his name again? Oily Orpiv, I think.
I once saw an apprentice dark mage polymorph his small chest and spill all his stuff. I would have laughed, but I didn't wanna be turned into a dark frog.
I heard you can fetch a nice iron arm from the dwarves of Kharaz-Arad.
The second one could be an arena master. Similarly to the sumo arena, there would be an arena in Mondedr. you could chat with the arena master to be sent there and a monster would be generated for you to fight. This fight, however, would be to death and the monster generated would be based on your danger level (of whatever is it called), so that it is always challenging for you. If you win, you get some money for the show. This way, you could get a steady income, but not without risk - maybe raise the comparative difficulty of the monsters generated as you win more fights, so after enough fights, the monster generated would be stronger rather than equal to you.