Thank you. Given that phone calls to FCO and the ATL baggage phone + two separate online forms have gone nowhere, here is my next move.
On the day of departure from Rome, I will seek help at FCO in whatever version of Lost and Found exists hoping this is in the secure area as I arrive terribly early at the airport. If that turns up empty, then once I land in ATL I will return to E SC and ask them where I can look since that is my prime candidate.