Okay. To me this looks like Cass. I'll also say that I wouldn't mind Cass wearing Babs's old costume. If anyone has the right to wear it now, it's definitely Cass. And with that, it makes me feel better about the possibility of Steph wearing Cass's Batgirl costume.
But I'm still uneasy about the idea of Steph being Batgirl. Feel free to correct me on this if I'm way off-base, but I feel like whenever she's had a "screw up", it's been because she was trying to follow other people's rules, live up to someone else's expectations, or prove her worth to someone else. She first made the Spoiler costume for herself, to spoil her father's plans, and although she's someone who definitely needs friends and allies, I don't think tying her down to someone else's legacy (let alone two peoples legacies: Babs and Cass at this point) will be good for the character.
(And can I get a "HELL YES" for no goddamn high heels?!? ILU, Phil Noto.)