Well, they aren't that valuable really. You can kill any NPC that's been turned hostile in a "lawful" way (corruption spit, drake spit, unholy aura etc.) Thundarr as well as Waldy, really. It's just Ruun who's very tricky, actually. I also remember getting Waldy hostile while equip-IDing some *armor* of hate. Killed him and his muscleless goons and just went on with the job normally. No one else gave a damn, IIRC.