The two teachers I feel know me best are my English teacher and choir teacher. I am planning to apply ED to Cornell, and they do not specifically state which teachers they’d prefer for letters of recommendation, but is it just an unspoken preference that the two teachers be core subject teachers? I believe my choir teacher may be able to write a stronger rec letter for me compared to my other core teachers. I am also already submitting a supplemental rec from my programming mentor.
I would use a core academic teacher for an academic LOR.
I would also use a core academic teacher. They want to know what kind of a student you were - work habits, performance, comparison to other students, etc. Unless you’re applying as a choral major, I don’t think it would be an effective recommendation.