Agree with you. Ski jacket that protect body from wind chill works well enough, I wore down jacket before but since it wasn't windscreen, so not as good as ski jacket. Furthermore, wear clothes that could fit in well, i.e. not to leave so much room under the jacket.
I highly recommend this: if you're going to ski, it keeps you warm against wind all the way from neck to mouth.
I used to wear: ordinary underwear, cotton turtleneck, fleece vest, a thin wool sweater (if it's extra cold), ski jacket, ordinary thick pants, hat, gloves, neck warmer, ear mug (only it's extra cold), shoes with fleece / fur.
Neck warmer. I bought one in Korea which is tight as it has no rope. I once bought some from taobao that has a rope to adjust, but it isn't good because not tight enough.
Are you going by group tour or on your own? If you're going to take group tour, mostly transfer on coach, then it's not necessarily to have neck warmer. If you will play sleigh, then you still need a pair of ski pants no matter how you do the tour.
If going on your own, and you expect you may need to walk in the street for a while, then a napkin is definitely required, a neck warmer is another option.
A pair of boots, not necessarily ski boots, but a pair of boots that keep your feet warm and provide reasonable anti-slippery.