The answer to question #1 depends on whether you want a suite guaranteed or are okay risking it. Also, depends on what type of suite you are thinking of (i.e. standard suite - penthouse suite).
The answer to question #2 is always book early and keep checking for deals throughout the year. You can always cancel a reservation if a better deal comes along. Case in point I have a room at Bellagio for October at $129/night based on a deal they were running in June. Same room is about $400 now.
Use fatwallet to find deals for the next year.
http://www.fatwallet.com/forums/trav...25/?lastpage=1