Most animals aren't doing anything you can reasonably call music if you want the words "music", "communication", and "language" to have any distinction. Your example of a whale using music to communicate is anthropormorphization.
I generally agree with your comments here, as far as my not-a-linguist training goes. I am a lifelong musician however, and there is one thing I've repeatedly experienced that does indeed seem to me like "animal music." Specifically, when I've played instruments in a certain pitch range (generally on the higher end), I have had birds come along and... this might sound crazy.. but they have started learning bits of my songs, and singing them back to me. IOW I've witnessed birds pick up and repeat some of my hooks. I'm not sure if they've been trying to communicate, and/or if they think that I'm trying to communicate with them. But goddamn, it has really felt to me like the birds are just joining in on and/or are trying to learn what they think is a good tune. And since there is video out there of what appears to be animals using expressive arts --dance (http://www.youtube.com/watch?v=cJOZp2ZftCw,) and painting self-portraits () -- it seems reasonable to think that other animal brains might also indeed be capable of the kind of artistic expression & intent that distinguishes "music" from the kind of "communication" one has a spoken language.