A movie Steph would be her third live action version in the last decade. She appeared in an episode of Batwoman season 2 (with red hair, so she looked more like Babs - the episode did involve Cluemaster though). She's also in Gotham Knights played by a different actress (and actually blonde this time). Neither show has Tim.
I'm not sure Cass is autistic either. She was just trained in body language and not speech, so she took a very long time to be able to speak in full sentences. That's nurture, her upbringing to blame, not nature, i.e. a mental problem.