1) For both GC hunting log entries and Book of X entries, you have to be alive when the target monster is killed.
It's not the dungeon itself you need to clear, it's get the boss kill.

2) Lady Amandine appears in both Haukke Manor and Haukke Manor (Hard) and from others I've heard that both versions count toward the book.
So you can go for the level 50 version in this case...