The estate of the previous owner of the home should have no claim at all. The house, including the walls and any insulation - no matter how eccentric - the previous owner chose to put into them, belonged to the owner of record.
The contractor had no claim either. It would have been a nice and neighborly thing to do to offer the guy a finder's fee - say 10%.
But not obligatory.
“The contractor had no claim either. It would have been a nice and neighborly thing to do to offer the guy a finder’s fee - say 10%.”
She did. He wanted 40%.
110%
Under English common law (and thus most American law), that is precisely the proper owner. The owner hid the treasure and presumably forgot about it or died before he could alert his family to its whereabouts. It seems most equitable that the money should belong to his heirs.
The contractor had no claim either.
Again, under the common law, the treasure trove belongs to the finder, not the property owner. Some states have rejected this, but I believe it's still the majority view. Don't know the Ohio view. Either way, it's an interesting set of facts.