My educated guess would say not difficult. Haven't heard any problems with 7 month booking window thus far. And by then the second phase will be open so it should not be that bad. Just my guess, though
Hard to say with limited history. We didn't have any trouble with Oct 2011 booking at 7 months. All size rooms and category were available when I called. Good luck!
I just booked a studio for a week in mid-december (2011) without a problem. Standard View studios were not available (for the entire length of our stay), so we opted for a garden view studio.