I love Lucy, too. She's a very special actress. Here are some suggestions, though. Take them as you wish.
Compared to the model's in your image, Lucy Liu's eyes are more slanted due to her very high and sculpted cheekbones, which are one of the most obvious and astounding features of her face. So I'd suggest doing some cheek sculpting and slightly repositioning the eyes slanted slightly upward. I'd also suggest emphasizing the epicanthic nature of the eyelids, too. Lucy's eyes are unquestionably East Asian, whereas your model's are quite ambiguous.
The mouth of the model in this image is actually a good first step toward getting Lucy's mouth right. It's hard to do. Her mouth itself is both small and large…a conundrum…and her lips can sometimes appear thin and other times quite lush -- but always a form of cupid's bow shape. In your image there's room for more lip-shaping along these lines, IMHO.
This model brings very slender legs to the portrait, and that's perfect for Lucy. But her upper arms are a bit fuller than Lucy's. And the breasts…uh-oh. Way too big for Lucy's. She's quite delicate and small-breasted. Not so tiny as, say, Audrey Hepburn, but this is an important feature and if you're really trying to "get" Lucy into your image, might be something you could adjust. I know of course that the reality of small breasts is not a Western fetish preference. But…well….