Q5: How do I fight liches?
A5: Liches are tricky opponents, mostly due to the Time Stop spell. I would wait until level 13 or thereabouts before tackling liches. Before then, your saving throws simply won't be good enough despite whatever defensive spells you've cast. It really hurts when a lich casts Time Stop and then Finger of Deaths half your party away. Wait until they have good saving throws, and you won't have too many problems. Breach and Pierce Magic will serve you in good stead here as well.
Q6: What's on the Bonus CD?
A6: There's a new shopkeeper named Jovul in the Copper Coronet who sells Icewind Dale-related equipment. There are some very good magical weapons here.
Q7: What's on the Collector's Edition CD?
A7: There's a new shopkeeper named Deidre in the Adventurer's Mart who sells Planescape: Torment-related equipment. She sells the most powerful armor in the game (Balduran's Plate, Robe of Vecna come to mind) as well as some decent weapons and miscellaneous magical items. Each bonus vendor sells 10 items each.