i'd name one tortilla the hun (pronounce the L's so it's like Atila the Hun), or captain beefheart, or purrgus mcmeow, or murdock. i'm no good at girl kitty names, my girl kitty is named winston smith.
if you do end up naming one caligula you could always name the other one antigone (i think that's you spell it...)
if you do end up naming one caligula you could always name the other one antigone