Ah man just ask her what sort of spells she does and how. Is she a Harry Potter witch or Arthur and the sword in the stone witch? I’ll assume the second (the first is just a wizard)
In my opinion WIS main stat. Witches are akin to medicine men or shamans in my mind (Terry Pratchett). They rely on their intuition, knowledge of nature and understanding of people (unlike wizards). Ultimately I’d ask your daughter what feels right.
I think focus split between Witch-y spells and potions is the way to go.
Do you want spells to be specific or open-ended?
Hex: turn target into frog for 1d4 rounds
Curse: requires sacrifice. do an effect with one way to remove it. Stronger the effect, larger the sacrifice (sacrifice just means something of value to player)
Polymorph: change into another body, object or huge animal!
Detect magic, etc
Speak to spirits
Potion brewing: make 1d4 potions (diff types of potions require different hearts of effort). Or simply make 1 potion with 1 action.
-new potions can be created with Hard rolls (and new ingredient?)
-healing potion/love potion/sleep potion/forgetful potion/etc
Cauldron: +3 to potion brewing (or increase number of potions made)
Witches ladle: Use magic effort when brewing
Mystic orb: see glimpses of futures/distant places
Animated Broomstick: like Alladin’s carpet
Familiar: could be an item!
Witches hat: +3 charisma
In retrospect I think solely potions and good milestones could be more than enough. With a few more utility based spells (talk to spirits, detect magic, etc) as “rituals”