What's the Name of That Book??? discussion

This topic is about
Modern Fairies, Dwarves, Goblins, and Other Nasties
SOLVED: Children's/YA
>
SOLVED. Dark fairy short story collection for middle grade readers, black and white stripes on the cover stories include children kidnapped by goblins, girl turning into a flower, a hotel destroyed, and two pianists tormented by fairies. Spoilers. [s]
date
newest »

Kidnapped by goblins:
I think this takes place in the 80s. Main character is a kid who's taking guitar lessons and when he's in the subway he notices some weird rats and maybe?? A man with a trenchcoat and hat? I can't remember. I think he follows them and then he ends up in a tunnel in which he's kidnapped by a group of goblins who force children to serve them. There's other kids, all from different time periods as time does not pass for them. I believe the oldest in terms of home period was a girl named Mary? Mary was their cook and made an escape attempt by digging a hole through the tunnel in the kitchen but she was caught and forced to eat their food. Eventually the main kid, who's been forced to play guitar for them, plays stairway to heaven and it freezes all the goblins and all of the children escape except for Mary who has been brainwashed by the food she ate and stays behind.
Turned into a flower:
Girl with a flower name is bullied by her sisters and mother and plays in what I think is a fairy ring outside at night. One day she wishes she could be beautiful and the fairies turn her into a flower, killing her essentially.
Two pianists:
Twin girls are concert pianists and were seen as perfect prodigies but the found fairies (possibly pixies?) In their pianos so they begin to torment them so the fairies enact their revenge and they're so hurt by it that they never perform again
Hotel troubles:
A hotel is doing something to damage the environment or to kick out fairies that live there or something so the fairies wreak havoc. Main character is a little girl who's dad works at the hotel I think.
The book had the theme of one (presumably fictional) woman who had researched all of these stories and been trying to expose the fae for being dangerous or something like that, I think she had a long name.