If the growth is above the graft, it is still a navel. Be careful to remove any shoots that come below the graft on the navel. They will sap the energy from the navel portion of the tree.
The peach died back to the rootstock. It is now probably either a peach
or plum. The peach rootstock could be used to graft another peach, but
the fruit from the rootstock will probably be inferior.

Thanks. The navel shoots are coming out the side of the 'dead' trunk. Will the surviving navel take forever to grow back and be deformed, or is this a minor setback?

Is the peach rootstock fruit edible, or not even worth the care? If so, may be a good first graft project.

The navel shoots should grew pretty fast since the rootstock is established. Just make sure you pinch off any rootstock shoots that occur below the graft. They will sap energy from the navel shoots and will overtake and chock out the navel shoots.

The peach rootstock might not even be peach. Some are from plum rootstock. You should be able to tell be the leaves. However, the fruit, if it makes, would be edible, but might not taste good. It would also have its own chill hour requirements. I would use it to practice grafting if I wanted to learn to graft.

That's a good plan. If I understand correctly peaches need a cross pollinated. So I could find a different variety than the one I already have and try grafting.

Most peaches are self fertile but set more fruit with a different variety. I would use a different variety that ripened at a different time to spread out the harvest.

I'll give it a try if I get the chance, thanks.