Thanks! What you seen in-game is about as deep as my thinking went into it. Having certain ingredients control things like different hair styles or things like straight vs curls could be cool things to build on, but were never planned. I was mostly focused on hair color.
The names primarily came from the size of the potions, because I thought it would make sense that tonics with more ingredients or complex recipes would result in bigger potions. So I made sprites for a small, medium, and large potion first, and then afterwards tied the bottle size to hair length. So "short", "normal", and "long" can be switched out with small, medium, and large (and are in several places internally).
If you meant seeing the hair tonics work on customers before they leave, that also wasn't planned for the jam build, but would probably make fulfilling requests more fun and satisfying.