When you buy containerized trees the first thing to check is the roots. Trees grown in regular smooth sided nursery containers will often circle or J-hook. They tree may do fine at first, but this will eventually cause root constriction as the trees get older. Remove enough media to check the roots and hand prune any roots that are circling the container. This is probably less of an issues for apples than for seed grown trees since the clonal rootstock will not have a tap root, but depending on how long they have been in containers, it can still be an issue.
I'm in 7A as well. I'm planting rootmaker trees which don't have the circling issue. With these trees, I can plant trees that are not dormant. this is largely because the well developed root system is not disturbed at planting time. They are probably close to dormant now anyway. I've been planting trees since early October. I'll probably continue planting trees into January and then start up again in March with some trees I'm over wintering.
We are fortunate in this area to have a pretty wide planting window.
Trees can be overwintered. One way is to dig a hole and put the container in the hole and then fill it with much. Another is to put them close to your house and mulching all around and on top of the containers. If you have an unheated garage you can try keeping them in there. The idea is to keep the tops exposed to the cold but not let the containers freeze hard. However, my recommendation would be to plant them now.
Thanks,
Jack