1. Do the materials in the pile continue to break down at all in cold weather?

> Yes! As long as they are above freezing they will slowly work. And, freezing and thawing helps mechanically break down the plant fibers so they will digest faster when it warms up.

2. As I rake and shred leaves this fall, what's the best use of them: add to the piles; as mulch around shrubs and flowers; dig into 'yet to be planted beds; or, save for adding to the piles next summer?

>I keep a pile next to the compost bin to cover the winter kitchen scraps each time I add them. If you have or can get grass clippings in spring, it's good to have leaves to mix with them. But they are also fine to put right on the beds. I usually spread them on top rather than digging in. The worms will work on them unless the ground is frozen.

3. As far as veggie peels and kitchen leavings over the winter, best to add to the piles or dig into new beds this winter?

>Either way will work!

4. I plan to cover the piles with a tarp this winter. Should I continue to turn and keep the piles a bit damp?

>Yes, although turning is not critical when the pile is cold and not doing much. Kind of up to you. Moisture can be regulated by watching the weather and covering or uncovering as appropriate.

I keep adding kitchen scraps to the bins, and would pile most of the leaves into one bin, and use them to cover over the additions to your compost bins.

Contrary to what some might indicate direct sunlight is not a significant need for composting. Many of us have compost bins that get no sunlight and that has no affect on the process.
Tox has answered your questions quite well so I won't add anything except my bins were constructed to I could place a 4 x 4 sheet of plywood over them to regulate the amount of rain and snow that the materials in the bin would get. Those hlp keep the material at a just right moisture level so they are not too wet.

Thanks, everyone, for these helpful suggestions!

Allow me to ask another:
I have a large structure in the backyard which everyone calls the 'Bel Air' Bird Sanctuary and Salon. :o) It includes about twelve bird feeders of various types. As you would expect, the empty shells of black oil sunflower seeds, as well as some of the millet, fall to the ground. Can/Should this be added to the compost?
I'm concerned that the millet seeds might survive and sprout next spring. Also whether or not the sunflower shells would, in some way, be harmful. (Don't ask me why I would think that!! Stranger things have happened.)
gary

Black oil sunflower seed hulls have an allelopathic effect on some plants. Not sure if that continues post-composting but it's something to research.

Black oil sunflower seed hulls are alleopathic, but once they are composted, they are no longer black oil sunflower seed hulls, so they should be not be alleopathic anymore. But when composting alleopathic materials, make sure that the compost is completely finished, so there aren't any bits of undecomposed things that may contain their original properties.

The stuff that falls to the ground stays on the ground... but I do clean out my feeders right into the compost bin. On occasion, I do get some millet and sunflowers sprouting elsewhere... If I don't like em where they sprouted, I weed em out and compost the weeds. Sometimes I just let them grow and the birds have it when they go to seed.