Might I recommend making a crafting station for her potions? You could make it a cauldron or something else witch-like. I feel it a bit strange being able to whip up your potions anytime anywhere without a station.

for the skulls maybe make it a one use respawn point for that character. I'd also suggest making the poison potion able to be crafted with 5 or so darts to make poisoned darts that deal high damage and damage over time. take the "poisoned food" idea and make that available for all the potions, making it so that you can pour the potion on food items to apply their effects. some potion ideas are a "brew of guardian blood" that can turn any tree into a guardian, a "brew of passivity" that make creatures to be passive for like 30 secs, a"broth of thunder" that make you immune to lightning damage and set of WX78's charged state, a "broth of giants" that doubles your stats for 30 secs and you deal 3x damage( this potion would be very expensive and would require late game items, maybe even some boss items like a deerclops eye), and a "potion of ants" that halves the stats of the drinker and reduces their damage to 1/3 of what it would be. maybe make her need a cooking pot nearby to make potions.