It might be cute to do a C name since you've got an A name & a B name..
My cousins liked unsual names too so they looked towards the end of the alphabet & came up with a Z for their first child, Y for their 2nd, then when looking for their 3d they realized they kinda had a pattern going & found an x name they loved, then stuck with the pattern & named their next 2 kids with a W & V. The oldest just had a baby & stuck with the family pattern naming her son with a U. I think it's a super cute idea! Except you could do the begining of the alphabet. :)
Here's a few of my name suggestions, I list a bunch of C names & other ones too, some aren't citys, some are states or countys.. but they still go with the theme..
Carson, Catalina Chicago, Chandler, Cambridge, Cleveland, (Love that name) Capriquet, Colombia/Columbia, Camden,Campbell (Or I like to spell it Cambell w/o the P,) Charlotte, Cheyenne, Cayenne, Cordova, Callahan, Cambria, Carmel, Clayton, Coloma, Colton, Colusa, Creston, Calera, Clio, Chelsea, Covina, Colusa, Castella, Courtland, or you could spell it courtlynn or whatever.. Callahan, Copeland, love love that name, it's a city in Ireland that I fell in love with when I went there, :) Camilla, Cansas, Canada, Caroline or Carolina
Augusta, Kenya, Britan, Ireland, Vienna, Dakota, Virgina, London, Aurora, Avalon, Boston, Sahara ( I like it with a z) Sienna, Phoenix, Sofia, Ireland, America, (although america ferarah is a real popular actress, but otherwise i've only heard a baby with that name once) Vicotoria, Sydney, Isreal (I've heard it pronounced Is ray ale.. Denver, Portland, Austin ( kinda a boy name but I love girls names like Jordyn & Kodi & other boys made into girls names. :) Montana, Acadia, Bristol, Geneva, Asia, Samara, India, Geneva
I hae tons but I'll spare you & end here. :)
Hope you find the perfect name & congrats!! :)