Am not a Frankie fan but I love Franny & Francy and I absolutely love the name Francine. It would sound so intellectual, artsy, free spirited and cool with Ida!
As for Kitty, I did wonder about Catherine/Katherine or Kate but I think I prefer Kitty with Ida (and you can even nn Kit or maybe just Kit as her name and nn Kitty).
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Felix or Stanley are gem names. You’ve a solid boy list! 