The Borders of the Land of Israel: Where Limitations Embody Infinity

1) the story is published somewhere. I don't remember where at the moment. I heard it from one of my Roshei Yeshiva.

There is a Maamar in the Alter Rebbe's Sefer "Hanachas HaRaP" on the Possuk "Bchol Beisi Neeman Hu" that I believe makes this very point. However, I don't have the sefarim here to look all this up.

2) The divine chariot has four legs that "hold up the throne". Of course this is a case of "Nasa Es Nosuv" that means the Merkava doesn't need to be held up, rather the Malachim holding up the Kisai (throne) as they are in proximity to Elokus are inspired and uplifted by it.

3) The four "legs" correspond to ChaGTa"M and are the four basic aspects of G-dliness. One of their ideas is the beginning of division, similar to what the Torah describes in Breishis the one river flowing from Gan Eden becoming four.

Therefore frequently Kabala divides the four into twelve or 16 or 64 (don't ask). These additional details represent a further distancing from Kedusha and Elokus and a further diversification from the Unity.

The number twelve is therefore quite common in such scenarios.

4) The twelve oxen as opposed to the eagle, lion and man are also alternative forms. As Rambam describes in the Moreh that each prophet has his own form.

So, the issue isn't the particular species of animal but a. the idea of animal and b. that they are more than one.

Answer: I know nothing about music and therefore cannot respond with wny intelligence. I hope you can understand that.
Thank You Rabbi Paltiel.