Will my gear survive in weather ranging from 0 to -6 degree temperature?

In the inside pockets, not outside jacket pockets, or backpack pockets.   And if you're not going to be using it for many hours, you might consider taking the battery out of the camera as well.  I lost half a charge on a 7d battery sleeping overnight on the lower slopes of Kilimanjaro.  Fortunately I had a second battery and (for better or worse), was a bit too 'drunk' from altitude to need all of the next battery during the climb.