So lets sum things up.
a) NPC will join if the building they require is already built.
b) They may require a quest to be completed.
Materials for the Trader:
Stone:
3000 (after persuasion) or 4000 in talmberg
Grain:
Uzhitz 160
Samopesh 80
Sasau 120
Livestock:
Ledechko 30 (Claims that his livestock is of lower quality)
Sasau 50
Rattay 70 (after persuasion)
Charcoal
Sasau 220
Ginger’s Friends 180 (If saving Ginger)
Gallows Hill 220
Rattay 220
Buildings:
Woodcutters camp:
Kunesh +35
Raspberry +40 (Will require judgement, may leave)
Trader
Kornelius +75
You have to complete quest aquarius, while he will remain without work. He might take position of the Bailiff when you step down.
Konrad Hagen - Can be asked but not known how he might join.
Tavern
Tavernkeeper: Adam +30
You have to complete quest Besmirched in his favor and return all stolen gold and family cross.
Alternative: Andrew: Can be asked, unknown if he join.
Aleouse Maid: Mirka +50
Will join if Timmy survives.
Alternative: Alehousemaid from Samopesh, unknown quest.
Patrons: Fritz and Matthew (initially -15 each, after judgement +10 each)
You have to complete series of quets in their favor. They offer training.
Bakery: Baker Silverter +75
Will show up upon judgement, have to be judged once again later.
Butcher: Kochwurst 50 or Brisket 45
Both will show up upon judgement.
Forge:
Swordmaster: Fink 60
Will join after Sword of Sheba quest.
Armorer: Master Ota +10 or Zach +70
You have to decide during quests in Sasau.
Guardhouse: Unknonwn
Nicholas in Talmberg can be asked.
Black Lukesh in Talmberg caan be asked
Stables:
Vashek +45 (Uzhitz, if you complete quest with lost horse)
Mark +55 (from Neuhof)
Church: Unknown.
Rathaus: Unknown.
Kornelius might take the office of Bailiff after you end with the questline, probably throught dialogue (havent tested yet).
Other NPC related Judgements:
Herbwoman - you may decide to keep her or drive her away. In first case you will get some profit and increase in population. (Not visible in village, probably the one north of Talmberg).
Farmer and his Wife - If you force him to be sober, he will produce additional 5 groschen. If you drove away his wife, population will decrease.