Can you possibly wait until late fall?
The weather is miserable now for us; it's not much better for redbud trees, and if you can wait, winter rains will get the roots re-established much better than any watering you can do between now and winter.
(And with TN's drought, the trees aren't going to put on that much growth this summer.)

To kind of parallel what Ann said, replanting the seedlings now would make keeping them alive a real challenge. Unless you dig a very large rootball relative to the size of the plant, you will decrease the root mass and make it hard for the tree to take in enough water and nutrients to survive the heat of summer. If you wait until at least mid fall, the plant will not have to work nearly as hard to stay alive and a smaller (normal size) rootball can be transplanted.

When you dig the hole where you are going to replant the seedling, make a bowl shaped hole just slightly more shallow than the rootball. You want the top of the rootball just slightly above grade when planted. Also, make the top of the hole at least twice the diameter of the top the rootball. This will help the tree get established quicker.

Use only original soil for backfill. If you do amend the soil (I generally don't recommend even this), use at least 2/3 original soil (the soil you took out of the hole when you dug it). If you do amend the soil, make sure to mix the soil instead of layering it. Don't use fertilizer unless you do a soil test and the test indicates you need it. Trees are more often hurt from fertilizer than helped without a soil test.

Water in well when planted. I usually make a small mote to hold in the water to ensure the tree gets enough water until it gets established. About two to three inches of mulch extending as far out as you can justify will also help. Don't use mulch thicker than 3 inches, and don't pile the mulch right up against the trunk/stem. I usually taper the mulch off so that it's about a half inch thick or less right at the base of the tree. Keep the area around the tree grass and weed free.

If you have any more questions or need clarification on what I've said, just let me know.

Thanks for the info, I had figured on waiting until fall, but wanted the ideas now. I love Redbuds and just hated the thought of getting rid of the babies.