Some things that I wouldn't mind seeing developed further:
How does Grimoire feel about happening upon such immense power? Does it exhilarate her? Frighten her? How does she feel about having potentially less-powerful teammates?
Does anyone in Grimoire's family know about her new superheroic career? What do they think about it? If they don't know, what do they think about the hero Grimoire? And what would be their ideal hero?
How much does Grimoire trust Ms. Mansion? Have they ever had any disagreements or arguments? What kind of hero does Ms. Mansion want Grimoire to be?
All in all, solid effort. I would like to see what more you can come up with.