If it looks like it's going to be a hard freeze, put them back in a protected area. A light frost won't hurt most trees, but it can damage those tender new leaves that have emerged to soon. So carry the budding maples back in or cover them if it looks like frost. You will probably start repotting in April. Most deciduous trees should be repotted when the buds are swelling, but before the young leaves emerge.
Evergreens can wait longer because they tend to bud later.
Don't repot when the trees are in soft growth. They need their energy to grow at that point, and they can't do without water. When you repot, especially if you cut a lot of roots, the tree will not get enough water for a while. After the initial soaking, don't water the tree and you will be able to tell the roots are working when the pot starts to dry out. At that point you can move the tree gradually into the sun and start watering.