Disney World in December (Christmas season)

[canadawithboys]

Thanks SO MUCH everyone! I would have replied sooner but have been caught up in a ton of stuff that hit my family all at once! You all are amazing! Such a wealth of info, I appreciate it!
So if I understand right... the decorations go up little by little from the beginning of November on... and are "complete" by a few days after the Christmas Parade... which is Thanksgiving weekend?
I'd ideally like to go:
A. When all Christmas decorations are up
B. When weather is hopefully warmest for that time of year
C. During as low of a pricing season as possible for that time of year
D. Low crowds if possible.
For those preferences... is first week of December probably the "ideal" time?