#1) Every location that the books in Mooshu are at are repeatable.
#2) None of the books are located in side quest areas.
Wrong Preacher. The book in Village of sorrow has the 3 candles quest. Where each time you light a candle in the house you have to fight 2 enemies, the 3rd candle you light releases the boss (Futu something?) But yes all book locations are repeatable