Here's a radical idea: instead of creating one new female character out of whole cloth, why not just change the gender of half of the existing characters?
Birthday parties are supposed to be the ultimate in frivolity--it’s literally a day all about you!-- but that’s also what makes them emotional landmines.
Were the vague memories I had of a group of magical children trapped in a library something I’d dreamed as a kid? And the kids were somehow from the future? And had to escape the library using both a precious ruby and the Dewey Decimal system?