I've found the secret room in the library with the snake figurine, but instead of finding the serpant wand I get a book. What's up? Where do I go for the serpant wand now?

I don't think that you have the right room. Did you put all 5 statues in their places in the library? This will active an elevator in the library to take you up to the secret room with the serpant wand in it.

Only 3 figures so far. Found in the sewers. 2 monkeys and a snake. Where are the other 2?
I've been floor to floor so much I'm just about lost moving around now.

I got 2 statues in room with 6 closed gates. There are 6 levers and slit for coin, you have to switch levers in some configuration and when you put serpent coins to slit it will open one gate. Another configuration next gate, etc. Also one monkey statue was in hand of one monkey - "temple monkey with strange item" it said I think, not regular monkey. This monkey I met in same room too, some statue in chests behind gates.