It’s possible she was talking about her biological father, but I’m tempted to say that she might have been talking about her foster father. In 3×13, Zelena said that Cora gave her up and that she grew up in Oz, which leads me to wonder if she was taken in by a couple from Oz.
Agreed that she was likely talking about a foster/adoptive father. If Cora gave her up, why would she give her away to her bio father, especially if he was a drunk? So I think Leo’s still a possibility for bio-dad.
I’m not convinced that Zelena actually grew up in Oz though. “Try growing up without a mother. Try living in Oz.” Maybe those two statements are linked, but they felt separate to me. If she’d grown up in Oz, I’d have expected it to be worded a bit differently.