Unfortunatley they really do stick to those schedules. We have been once in mid-Jan. and once in very early Feb. Both trips we had mts closed, buzz closed, etc. Last trip we went the week after Pres. Week and everything was open, it was great.
Buzz closed when we were at Disney last week. Luckily we arrived in time to ride it. I had made a note in my book to make sure we got to Buzz before it shut down for refurb. I'm so glad I made it priority because DH and I loved it! We had never ridden it before. Sorry it will be closed for your visit! I hate when that happens. Jaws was closed at US this time and along with E.T. it's my fave! I was so sad.
While it is possible they will open a day early, I doubt they would try. It almost seems that the refurb dates wind up sllipping a little because of unforseen problems that come up.