Thanks! That false positive needs to get fixed and I keep putting it off. I'm aware of it and it'll get seen to eventually haha.
Potion upgrades will be on Ellie's tree, and they are on the way. Very likely showing up in the next update in some form - but there's likely going to be more iteration later on in development as well.
I'm just starting to get the fall gameplay stuff implemented, but winter and spring will also have different actions you can take throughout each day. The goal is to to slowly shift the types of things you do each day as the inn grows.