UPDATE
Just spoke with my neighbor He said yes his cat was out that night/ early morning. He also stated his cat had some kind of bird skin it had brought in that it was licking. He also stated he saw his cat coming from my yard, and had been going to talk to me too see if it was one of mine. He showed me some feathers that matched these quail. He promises to keep his cat in the house during the night as much as possible. He offered to pay for the bird, and said "if you see him near your pens again take what ever action you need" I did get this all in writing as well as audio.
I turned down his offer to pay as it was only one bird. So Id say in a nut shell it all seems to have worked out with nothing else being harmed
Daren