Interesting picture. By the way I made a few Batman based characters on the Monster High Fandom Wiki. One of them is the son of Batman and Catwoman who has a relationship with Toralei similar to his parents relationship. Another is the daughter of The Joker and Harley Quinn who unlike her parents is not crazy and has a crush on Batman and Catwoman's son.
I have more ideas for you like Cleo De Nile as Talia al Ghul,Gil as King Kraken,Spectra as Gentleman Ghost, Slo-Mo Deadovitch as Solomon Grundy, Heath Burns as Phosphorus Rex, Jackson Jekyll as Anarky. For Abbey I think she will perfect at Lazara aka Mr. Freeze's wife.
OMIGOSHOMIGOSHOMIGOSH ILOVE IT I LOVE IT I-*dies from the epicness of two of her favorite things becoming one* Hi! this is RWZ's spirit! She just wanted to tell you she loved it so much, and wishes someone would write a fanfiction cross-over for this. And she only had one question, who would be Batman? Would he be someone else? Or would he still be smexy old Bruce?