Viewing the Trailer it looks like the villains will be,
1. The Joker (Obviously)
2. Harley Quinn (Obviously)
3. The Penguin (The iceberg lounge is owned by The Penguin )
4. Two Face (From the Uncle Sam posters)
5. The Black Mask (from seeing the Sionis sign, Black Mask's real name is Roman Sionis)
6. Catwoman/maybe ( A quick flash of a black cat jumping on the fire escape)
Given Catwoman's history, it's probably hard to even call her a villain... If she's even in the game, she'll probably be ambiguous at best, serving her own needs.