I had a coral bark maple at my last house and I loved it. They’re generally quite hardy... I’d look out for nasty scabs on the trunks because I wouldn’t want those damaged. Wouldn’t want it root bound... otherwise, can’t think of much else. I’d probably keep them in the pots in a sheltered location until the spring if you live where the ground freezes.

What you need to do is go look at them and see if they are in acceptable condition.

As skmom has said, check if the bark looks smooth and healthy: no scabs, no knots, no splitting, no cankers https://www.gardeningknowhow.com/ornamental/trees/maple/maple-tree-bark-disease.htm, and if the tree is nicely branching.

Quite likely the trees are root-bound so you will have to open the root ball when planting. I would not do that during dormancy, so you will have to wait with planting until spring.

In Zone 8 pruning the roots now on a tree hardy to Zone 6 shouldn't ordinarily be problematic. And new roots will come from the cut root ends as soon as spring bud break occurs. With working on the roots after spring bud break meaning that already initiated roots will be getting cut off.

The annual root activity schedule for cold climate adapted woody plants is:

Spring: new roots develop, after stem bud break

Summer: existing roots grow some

Fall: existing roots grow a lot - 60% of the annual increase in length - after stem buds have matured

Winter: plant basically hibernates, with little or no root growth taking place

I buy discounted trees and shrubs from my favorite PNW nurseries all the time. Most of them are in a very good shape but they do tend to be rootbound and/or need a bit of corrective crown pruning. I do that upon planting in early spring. In fact I quite often completely bare root the plant to inspect the roots and trim those circling or overly long ones. Most deciduous plants take this sort of treatment quite well. I once did that with badly rootbound Camellia japonica and she didn't seem to suffer either. I would not try it with most conifers or Magnolias as these are said to be a bit sensitive to root disturbance.

No issue. I actually look for plants at the discount area and they do just fine. Go for it :)

Conifers are one of the least bothered groups, look how important they are to bonsai effects for instance. Where annual cutting back of the roots, in order to dwarf the tops and allow continued use of the original container is par for the course.

The trick with magnolias is to not cut the roots when deciduous kinds are dormant. Or cut them back too far at any time, same as with other trees and shrubs.

Discounted plants can have water mold infestations that may not be apparent to the unaware. Which may then spread out from infested specimens after installation on home planting sites. Anywhere container plants may have been allowed to sit in puddles or be splashed with dirty water they may have become infested. It is a multi-million dollar problem for container plant production operations in the hot and wet conditions of the South.