Actually, I tried hard to find any comments at all by Kennedy about the Kosovo war and came up with nothing. I find it hard to believe he didn't have a speech or two on war -- since he loves to take to the floor these days to bloviate about 'the greatest responsiblity we have in the Senate."
Actually, several times when people got up to speak about Kosovo, he'd take the floor right after them and give a speech about a "Patient's Bill of Rights" or some education boondoggle. For the record, however, he did vote against the McCain-Biden amendment (by voting "yes" to table it), so it's been hard to catch him in hypocricy -- but i'll keep trying.
You were thorough on this. Try his voting record. That will speak volumes, I'd think. Seen it posted somewhere that he voted NO on most actions to use our military. But don't remember where or exactly which ones.