If you have created NPC companions of your own by hiring Mercenaries from Anoriel Eight Eyes (found initially at Oleg's Trading Post and then later in the Tavern in your Capital (once you build one there), do NOT use them as Advisors. They have a built in negative value in resolving Events (-4 or -5, can't recall which). Although this can be improved by boosting the relevant Ability score that relates to the Advisor role you assign them, they will never be as good as the NPC companions that are available by default (Harrim, Amiri, Valerie, etc). Obviously you can still use such NPCs on adventures and just use the prebuilt ones as Advisors. It is still advisable to give your advisors items to boost their Advisor stats. The relevant Advisor stats are as follows: Military = Str, Regent = Cha, High Priest = Wis, Treasurer = Int, Councillor = Wis, Grand Diplomat = Cha, Warden = Con, Magister = Int, Curator = Cha, Minister = Dex.