SRS, skeletal dysplasia or Williams Syndrome?

Hi all! My baby is 8 months old, she was born with 1 kidney, she weighted 2.420 kg , she had hip dysplasia, low muscle tone, Reflux, she has Cows Milk protein Allergy, renal tubular acidosis she is really low in her height and weight (at 7 months old she was 5.400 kg and 61 cm) and she is a little behind her milestones. We are seing a geneticist and we will have our next appointment this friday , for what I know he suspects Silver Russell or skeletal dysplasias, but mu little one smiles SO much… I learned a little about Williams Syndrome and it confused me more… my girl smiles at everyone and also wants to go with anyone who is close to her, even people she had never seen before. I dont think she has the facial features but I am so confused. What do you think?