To awnser your questions
1. the lich is maybe a level differnt between the others you have faced he still is killable.
2. the scroll to the elf's is at the archers guild after you rescue a family from bandits you talk with him and he will reward you with the scroll.
3. the 2 guilds you listed Archers and Assasins guild you cannot join them.
hope this helps you out.
