1. Third sick one - with pickpocket level 2 you could steal one potion back and heal the third. You could also kill one of the cured and get the potion from him/her without reputation loss. However either somewhat defeats the purpose - the point of the quest is for you to decide, who lives and who remains sick.
2. The sword you miss is indeed in Iona's dungeon, behind a secret entrance, which opens when you lit a candle in a pentagram. This and the entrance to the lower levels can be found by looking in the locked thread "complete maps in Divinity" at the beginning of this forum (Kiya's site would be my recommendation)
3. Finding SHRIMPO - in the northeastern part of the cemetary, find and read the names on the gravestones in this order (S.H.R.I.M.P.O.) - and it will appear!
4. The 4th treasure map - if indeed it is the one from the dwarven mines you are missing, it can be found in the cell next to the mine entrance. It is named "scroll" and you need lockpick level 5 or telekinesis (2 or 3?) to get it.
