Give them OOC rooms for their OOC chatting and they should be happy being IC outside of them. When out of leads, players will resort to combat as the simple way out. Make sure they always have other obvious options to try if they're stuck. If a door is locked and they don't have the key, make sure there's a back passage, or strange writing on the door to look up at the library. So long as there's non-combat options to explore, they'll be very happy.
Achievers like to gain gold, skills, and social status.
RP is usually rare, time-consuming, and has no tangible profit in sight, so achievers avoid it like the plague. Since the only way to advance in most codebases is to kill mobs, achievers do that. If you give them the possibility of being merchants, crafters, civil servants, owning farms and workshops, and if those options are as profitable to both gold pouch and skill list as serial killing but without the risk, they will opt that way in a heartbeat. Killers will always kill, because that's what they enjoy. Have NPCs react to them as criminals and tyrants, use them as your bad guys - you won't even have to force them into it, they often act out the role very well themselves.