I think there's a good reason these two mediums both rely so much on the term "composition." Line refers to the movement of a piece, which is why I feel like it's congruent with placing the notes of a song. Just like how composition determines where the subjects are in a painting, it also determines where the chords of a melody go in a sequence.
Light is arguably the most important aspect to consider when drawing because it casts shadows//reflections, which make it possible for us to see. Using these tools, we learn how to carve out the basic forms in a still life.
If we apply this notion to music and ask ourselves what allows us to "see" the basic form of a song, we end up with sound, which essentially translates to rhythm or tempo. These are two things every song shares, no matter what.
It's interesting because dark//light and rhythm//tempo are two fundamentals all pieces have in common, yet every creation remains unique.
And this is why I think instruments are the most comparable to color-- wind or strings, bass-heavy or acoutstic-- these all translate to stylistic choices. They aren't technically necessary to make a song, (just as color isn't necessary to make a piece of art) but they help to add individuality.
And sure, if you're painting and want to be abstract you can use two colors that don't go together, but the piece generally looks more cohesive if you stick to color theory. This remains true when considering music theory.
I know next to nothing about composing music but I really love art and these are the comparisons that made the most sense to me!