Thank you both for your replies.
Yes, I believe I am wanting "deeply modal" concepts

- and keypeg, this is interesting regarding instruments changing modes. Right now, it is for me (I've never had a student hardly even want to learn a scale, let alone learn about the modes, let alone learn about those in a deeper way) but may perhaps be useful in my teaching, eventually.
Perhaps I am just being silly, but it seems there's this whole other(s) dimension to it ... there's some kind of matrix that I want to better understand. For example, I was looking at Bach's invention number 1 again, and I thought "What if, instead of just thinking about these motifs being transposed to represent different chords within one Major scale, he were thinking in terms of modes?" ... and then my head and my guts went crazy

. Today I have a rest from my head and guts, and I'm just kind of existing

.