Hi anon! Sorry for the late reply haha
I will be honest, I haven't thought much of how magic would fit in! But I think that there are so many exciting ways to execute it. Each 'district' could relate to a 'coven' - in this case D12 would specialize in Abomination magic if we're following Amity's main powers? Although I think Bard coven is more suitable for the D12 vibes.
D2 - masonry+weapons/soldiers/ Construction cvn, Abomination cvn
D3 - technology/ Potions cvn
D4 & D10 - fishing & livestock/ Beast keeping cvn
D7 D9 & D11 - lumber, grain & agriculture/ Plant cvn
D8 - textiles/ Illusion cvn
D12 - coal/ Bard cvn??? but this is only cuz I'm tying it to the covey's influence lol
Not sure where the healing coven fits into this, but it doesn't have to anyway.
Or we could go the other route with glyphs as you've mentioned! Maybe the 'district' folks don't have access to magic? So they are given some form of glyphs in place of weapons at the cornucopia.
No worries on the long rant!! it makes me really happy and appreciative that my silly drawing and idea tickled something in your brain!!!