This is heart breaking, indeed. You have tried so many things, talked w/ many, sought advice, guidance and ideas. Talked w/ the vet. I guess I'm not sure how you failed.

Oh how I wish they could talk and tell us what is going on!!!!

Which just caused a thought to pop into my head. Have you tried that cat "talker" some folks on here have used? Candace will know who I mean, and Laura had good results. One last try perhaps?