Ward and the Balkans in the 1990s

Some years ago I reflected on the Aidonia Treasure and the way that it was displayed by Michael Ward in New York (1993). The treasure was subsequently returned to Greece.

I then wrote about a silver repoussé plaque that surfaced through Ward and Company Works of Art, New York, in the mid-1990s, and three bronze helmeted warriors that appeared in 1998. It has been suggested to me that these items were found with the so-called Koreschnica Krater (although its route to the market has not been disclosed). 

I am intrigued by the extremely rare gold-figured phiale showing Thetis and the armour of Achilles that surfaced through Ward and Company in 1990. Some of the best known examples of gold-figured silver plate were found at Duvanli in Bulgaria.

Where did Ward and Company Works of Art acquire these pieces? What is the authenticated documentary history for them?