Trisha Elric from Fullmetal Alchemist, Sohyon from The Beast Player, and Bronagh from Song of the Sea have much more impact on their children than Coco's mother from Witch Hat Atelier does on Coco even though they only have little time devoted to them.
On top of that, Ed and Al from Fullmetal Alchemist and Elin from The Beast Player are much more determined about their goals—restoring their bodies in the case of Ed and Al and learning about the secrets of her mother, Toda, and Royal Beasts in the case of Elin—than Coco about turning her mother back to normal and learning about magic to do so.
So far, Shirahama has never expanded on:
Coco's comment in Chapter 1 that she's memorized every spell in the Brimmed Cap Iguin's picture book after a forbidden spell turns her house and her mother to stone.
Tetia's comment at Romonon that the spell to turn people into statues of gold is similar to the petrification spell.
Iguin after Romonon even though he spends a portion of the series watching Coco from afar, hoping for her to liberate magic.
