I love
Francis on a boy and
Frances on a girl, just the way it's supposed to be. Would hate
Francis on a girl or vice cersa, though.
Frankie is an OK nn for either, though I personally would prefer both Franics and
Frances without nicknames.
I don't find mother and son having a similar name any more bizarre than father and sons or mothers and daughters sharing a name, especially since
Francis and
Frances are not the exact same name, but the masculine and feminine forms of the name. I even pronounce them differently.