Frankly I'll be shocked if there is nothing available for that period. Yes it's December, but we're still 7 months away and One Bedrooms reportedly have the lowest demand of any room class.
Even if they tell you they can't get you the entire trip, ask them to look for individual days at a single resort. Due to their size, SSR and OKW are probably your best bet. Then, for any stray days you cannot immediately book, go on the waitlist.
SSR should continue opening new buildings all summer, so if there isn't a room in memebr inventory now, there should be in another couple of months.
Be sure to check back tomorrow and let us know how it went.