If your only going for 1 week - one jacket will be more than enough.......
Cant comment on the snow sorry....Im going on Sat too and really hoping for the best....I've heard that you can still ski at the top, but with the warm weather out there, god knows how long the snow will last....
been there 2 weeks ago, ski is possible at the top, but very busy on lifts,i took 2nd jacket for night time but only wore it twice, and that was only cos id taken it...