I'll give it a go.

She is a member of an all-female organization. Membership is obtained by birthright -- each member brings her first-born daughter into the organization. Training starts at age 4, with each girl's training determined by a combination of her aptitudes and the (perceived future) needs of the organization. Her training emphasized hand-to-hand combat and computer skills, although she also has basic-to-moderate competencies in half a dozen areas that would appear to have nothing to do with each other.

Her superhero costume would be monochrome. I'm not sure which color, but I'm thinking one color. I'm also not sure about the design of the costume, but she would emphasize ease of movement -- no hobble skirts, for example.

All I can think of is how her fam was super academic (the mom with the rats! The Sister with crazy research!). Did she become a superhero as part of all that somehow? I feel like it would tie in but I am not a big superhero person.

I like that. And the diplomatic upbringing should be in there somehow.

Clearly, her best superpower is arguing any issue with purpose and savvy and receipts.

are all the other heroines in the book, ones pulled from sources like comics, books, film, or tv?

are the descriptions of them going to identify their source material?

No, they're all original creations (thus the challenge!) He wouldn't weigh in on what his inspirations cane from or anything.

Gingham, a slight obsession with grossing people out for fun, and nut shots.

That's such a cool project.

I'd say something along the lines of the ability to remain calm and collected in the face of virtually any trauma. (In addition to the SuziQ's reference to her infamous links, need I remind everyone about her visit to the Precious Moments Chapel or that she saw Carrot Top Full Monty and emerged from the experience with sanity and eyes intact?)

Snark that can kill, but only sometimes. Maybe home and away hero costumes: One in silver, one in pink gingham. everyone wants to be her sidekick.