As a Joker fan... I really hope so too. I don't want Ayer ruining him more than he already did. No on the Harley/Ivy thing though. You know they'll write it terribly, and just play it up for titillation. I kind of hate how Ivy's character was reduced to a supportive best friend/occasional fuck buddy. Character used to be so much more.
Also, reminder that Ivy isn't a healthy relationship for Harley either:
Here's Ivy about to choke out Harley over a fucking plant. Ivy used to be an insane criminal with character of her own before she was reduced to Harley's supportive friend.