If you're going to mulch, pine needles are probably your best bet. They're light and airy enough that they won't crush your seedlings. Cedar mulch or wood chips are probably too heavy.

You might want to try a Styrofoam rose cone cover over your seedlings and then mound up pine needles around it to protect from deep freezes. I use them on my sabal minors to help them pull through the winters here in Michigan.

I would mulch heavily over containers and place large rocks nearby. The rocks for some reason help keep it warm. As you now know, AK has had a big freeze and its not too late to add protection.

Doesn't sound like something that is going to be hardy in USDA 7. I would have tried to overwinter them in pots indoors. Outdoors they will need whatever is sufficient to keep hard frost from getting to them.

bboy that is what im dreading. But they were sold as being hardy to my area.
They may not make it through the winter
there are really pretty and kind of rare.
Arkansas winters are usually mild though so i hope they can survive until they get a little older, that way if we get a really bad freeze they will be ok?