I think you're right with Emily Ratajkowski, the eyebrows are a match and the blemish on her left cheek seems to match. I think he sometimes doesn't make them match too closely, I thought his Emma Watson was a bit disappointing.
S.
Before I saw the last few promo images with the tips of her pig tails colored red I was thinking Margot Robbie. Some of those promo images are definitely Harley Quinn inspired.
Not familiar with her either but it looks like she's in the same movie (Suicide Squad) as Margot Robbie so I guess that's where the inspiration is coming from.