I'd suggest grafting the branches. I've grafted many pawpaw trees using a chip bud.

Here is a link that might be useful: mrtexas

You may be better off doing bark grafts with that size trunk. Do several all the way around the stump, and then select the strongest for the new top. The others will help the cut heal over. The stock will try to push lots of new growth, so you may want to rub the new shoots off to force all the new growth from the scion.

Another option that may be less risky, would be to cut the top, then let new shoots grow up from below the cut, then chip bud to them later.

I've chopped some off at ~5 ft, about 1-1.5" diameter and stuck 2 or 3 bark grafts on - none took, but I can't swear that my scionwood was good.
But, I've had close to 100% takes grafting onto limbs pencil-size - and I've done either whip & tongue or simple bark grafts - doesn't seem to make much difference.