@cowtownbrown, I apologize for the gender confusion.
Please understand, I’m not discouraging you from submitting a supplement. I just want you to be realistic about how much of an impact it will have. I applied ED to Yale (in the days when they had ED) with a letter from Mr. Parisot and got rejected, though I got into Stanford, Harvard, UChicago, Columbia and Penn. It may come down to something as simple as direct competition - are you going to be the strongest 'cellist applying? When I applied, there was a Brazilian student living with Mr. Parisot who also applied, and who got in (and who has since gone on to have a distinguished music career). It may have been as simple as the adcom making a direct choice, and if that was the case, I can’t fault them.
I applaud your commitment and zeal for the 'cello. Just be realistic about it.