I like
Anna.
Anna and
Katherine seem like pretty perfect names, as far as being respectable and strong and feminine, in my opinion. They could go together well for a FN/MN.
I was recently thinking of how nice
Katherine is because you can have be a fully formal
Katherine or a cute
Katie, and both are still classic.
I can't use either name for several reasons, though.
Otherwise, have you considered using your own middle name or another family name as a middle name? My mom gave me her middle name, so it's something I can't not like. A nice way to tie family together I guess.