First of all, there already is a Catman in the DC universe. Several of them, in fact, but the most notable is a Batman-like fighter (ex-wrestler, iirc) who currently trains "human-strength" members of the Justice League (such as Black Canary) in hand-to-hand combat and equivalent mixed martial arts to hold their own against super-powered opponents.
A "Catwoman-man" does sound like a neat idea, though it was done to death decades ago: The Scarlet Pimpernel, El Zorro, Robin Hood, every heroic pirate ever, James Bond... you get the idea. The "Dashing Rogue" is a centuries-old trope, and Catwoman is already the gender-swapped version of it. Could it be time to revive the trope (outside of trashy romance novels)? *shrug* eh... sure, why not. Knock yourselves out, ladies.
As far as a female Punisher... yeah, I could see that. I don't care about The Punisher in the slightest, and didn't particularly like Kill Bill (except for the amazing, over-the-top choreography), so I have no strong opinion on it either way. In my estimation, revenge for its own sake only goes so far as a motivation, and after that it's just mental illness. On the other hand, I find myself more invested in The Wolf Among Us than I would have expected, so maybe there's something to that. Who does the "revengeancing" is largely irrelevant, so long as they have the requisite tragedy and can justify continuing week after week after the initial push gets resolved. (I mean, come on... it's not that hard to find and kill someone when you know for a fact who it is and they aren't actively hiding from you.)
And Nexus... holy crap, does that sound stupid; not gender-swapping the character, the premise in general. Then again, the premise of Ghost Rider sounds pretty dumb too, and I kinda like that character... come to think of it, Ghost Rider is also "afflicted with justice" and could just as easily transfer to other people, but would that really change anything? (other than maybe the jacket) unlikely. Flaming skeletons don't really have gender anymore. (Yes, I know there are differences between male and female skeletal anatomy, but hardly dramatic enough in comic-book action context, right? Most people couldn't tell the differences at a glance.)