I know Grundy fans won't want to hear this but.. Cat stance makes all command grabs whiff. If I go into cat stance, both walking corpse and the trait grab whiff. Not only that, but 112 can be cancelled into cat stance on block -- so if you try to punish me, I can cat stance 1 and you eat a full combo.
Cat stance is even low enough to make your d1 whiff -- so no counterpoking for Grundy; full combo on a read.
Also, if you block my 112 I can just end it with whip, and now we're practically at neutral.
Didn't want to discourage you, but just thought you should know
Also for the catwoman mains, do not just throw out the whip trip in this matchup.. If it's blocked Grundy gets a free swamp hands (it's -33), and if he has a bar that means full combo for him and pressure. The reward doesn't outweigh the risk.