NPCs can be hired for a broad range of activities and on a broad range of terms under the contract system. They will probably perform those tasks autonomously, but you might be able to give them fairly detailed instructions, either through contract terms or through something like the scripts that operate as task setting rules for OPCs (player characters that persist in the world when the player is offline).
Contracts are described in DJ 7, which is still (I think) the last word in the subject. Offline Player Characters are described in DJ 3.
I have a long post analyzing contracts.
https://chroniclesofelyria.com/forum/topic/30605/of-contracts-and-commerce-a-tldnr-post
NPCs will be modeled psychologically (again based on last word). Markof’s post on that from a year and a half ago is still the best analysis.
https://chroniclesofelyria.com/forum/topic/22078/lets-try-to-understand-our-neighbors-the-npcs