Miss Honey has the best songs in the show, and, in my opinion, the best songs written for any character since Caroline Thibodeaux. Lauren didn't come off as too old to me, mostly because I was just bowled over by her voice.
The thing about Miss Honey (at least the way Lauren played her) is that yes, she is mostly shimmery high notes, but her speaking voice can drop way into the lower register. The duality is the most important part of her character. She's not a delicate creature, though she appears that way, and that's the point. She's a small but stubborn fire and her voice needs to bolster that.
My pick would be Christiane Noll.
I know you.
I know you.
I know you.