Well, Eliza's cat wouldn't meet those criteria, but Eliza was maybe still right. (Hope Minty is continuing to be well, Eliza).

However, rather than a premonition of the cat's illness, I would suspect that he hadn't been behaving normally, but not abnormally enough for any real concern, just enough to create a subconcious feeling that all was not well.

I experienced that one time when I was working abroad and came home to find my wife was ill. It was only later when one of my colleagues said that they all thought I had been behaving a little bit out of character (not badly or anything like that, just a bit odd) that I realised there I may have been picking up something different in my wife's voice during the calls home.

Food for thought...