The Forty Elephants was a real-life girl gang that terrorized London for decades. They did in fact have a Queen, although I don't think her name was Lucy.
This fictional Queen Lucy is named a character of the same name from the Jekyll and Hyde musical. The musical Lucy is one of Jekyll's love interests (the J+H musical was deeply uninterested in passing the Bechdel test), but you won't find our Queen Lucy singing a rendition of "It's a Dangerous Game" with Mr. Hyde--or if you do, she'll be the one creepily looming over Hyde in a fluffy fur coat. And Hyde would be totally into it.
Also, I'm late to the party as usual, but thank you to everyone who left me birthday messages in the comments here and on the roleplay forum!! They really warmed my heart!