Sorry to hear about your challenges.
First - how old are these trees and have they fruited before?
further - I don't think fertilizing, especially with organic inputs as you mentioned, would have this kind of impact unless you put pounds and pounds per tree.
I also don't think cicadas target the fruit. However - they certainly will target your pawpaw BRANCHES of about pencil diameter for laying eggs. The females make slits on the underside of branches and insert their eggs. It doesn't cause immediate problems but by the end of the year and into next year, there will be wounds and you may have dieback of the branches (not of the tree itself).
It's POSSIBLE some of this activity has inadvertently dislodged fruitlets. Also, birds will peck at them, at least here at my place, though not in great numbers.
I was asking about the age of your trees because young trees just flowering/fruiting for the first time may not be mature enough to hold many or any fruits. Sorry if you know all of this already but flowers can appear to be pollinated with baby fruits while in actuality the pollination is incomplete. These will look like tiny bananas and can hang on for a couple weeks or more but will drop in late spring.
Then even fully pollinated flowers that produce fruitlets can still result in dropped fruit in the June timeframe. In fact my trees are dropping up to golfball sized fruits right now. This is natural and simply the tree thinning itself because the fruit load is too high. My trees are fruiting for the first time so the amount of fruit remaining on the tree after this dropping is not high (but low-moderate). Even mature trees will drop fruit in early summer.
So all of that is to say it could be totally normal!