I've never been fond of the various Cornelius books myself (too jumbled and fragmentary/non-linear for my taste).
Of the two, Una seems to be a much more competent, dominant personality. She also seems to have a penchant for uniforms and for masculine dress.
Catherine's personality seems to be much more unformed (except that she seems to be a sexual masochist).
Given those traits, there should be a lot of available female figures that represent those extremes.
Given that they are nominally time travelers, I would expand your search into the Artizan Thrilling Tales range. There should be some useable figures there.
For instance, the Artizan female Sky Pirate would make an excellent Una:
"Agent Lake" would make a pretty good Catherine, too.