Well, Heather, given the fact this is early March I would say the chances are very good if you are persistent about checking for vacancies or cancellations every day. You can check online for arrival on 12/30/17 and departure on 01/01/18. It should work because when I plug those dates in and leave it open to all resorts, it shows vacanies and availability in other WDW properties. I was worried that the "next year" system issue might slow you down until rates were set for next year this summer but that does not appear to be an issue.
So keep checking and calling several times a day - be persistent - and I'm confident you can eventually get those dates.
Bama ED
PS - my DD who applied for DCP finally moved out of "In Submission" and passed the Web based review and had her phone interview yesterday for 2017 Fall Advantage (or just Fall if she can't get Advantage). I'm REALLY hoping she gets any kind of offer (she applied for just about anything except for a few things like lifeguard - but even QS, Housekeeping, and Custodial (her Mom and I chuckled at the last two)). If she doesn't get an offer, she'll be crushed - it's been such a big dream for her the last few years. We have our fingers crossed.