MY GIRL!!!! I think this first one is more canon than HC, but I like to think she's prickly on the outside but actually really nice once you get to know her.
She has a hard time making and maintaining friendships because of how prickly she seems, and the fact that her interests aren't typical of those her age. Though they're very different, I think Kay Faraday would be one of her best friends because they met when they were kids and (imo) seemed to click there despite their differences in personality. I think they'd terrorize Edgeworth together.
Though Capcom refuses to ever let them interact beyond a scene or two, I think Franziska and Maya would get along well and could bond over how they both shoulder big responsibilities for their ages. (Maya - Fey clan responsibilities and legacy; Franziska - von Karma name and legacy)
Since she works with Interpol in Investigations, I think her investigative capabilities are top notch, and she also speaks multiple languages due to all of the globe-trotting she has to do!