If its PLC it will drop some/many/all of its leaves depending on how bad. It will leaf back out. Best you can do is give it some nitrogen fertilizer and protect your trees during dormancy with copper or some other spray that is effective against PLC.

I have one full sized tree that lost almost every single leaf. Its leafing back out now with all the warm weather we've had lately.

I'm wondering if the soil is too wet where I planted them? Its still moist even though it hasn't rained much over an inch in the last two weeks.

"I'm wondering if the soil is too wet where I planted them?"

Peaches, and other stonefruits, require excellent drainage to do well. Only you can answer if the location is too wet, but if you dig down a few inches and the hole fills with water, it's too wet.

Peaches with wet roots will have leaf yellowing and extreme leaf-drop...to the point that the entire tree becomes bare. One or two seasons of this is enough to kill the tree.

If you have few locations available to plant your tree, you can adjust the tree by carefully removing it. Build a ring at least four feet across with landscape bricks, to a height of 8-12 inches. Line the inside edge of the bricks with aluminum flashing to keep the dirt from washing through, fill with good soil/organic content, replace the tree, and mulch the top layer.

This isn't the best fix, but may allow your tree to survive wet periods without adverse effects.