Am I right to think that quests like Waitress, Blacksmith and so on doesn't increase stats? Slave guild quests should increase Charisma. Wizard Guild Wits, Warrior Guild Strength, Worker Guild either Wits or Strength depending of the quest.

As a side note there's no way to increase Charisma anymore except Charm training during a date since Social skills have disappeared. Maybe slave training could increase Charisma.