My bet is that Moon gets both Popplio and Rowlet since she's both a medic and an archer. Lillie will naturally have Nebby when she appears and Hau will be like Wally and Shauna where he gets a different Pokemon as a starter.
I can see Hau get pichu since Alolan Raichu does seem like his ace considering reports where his Alolan Raichu gives players difficulty beating it. I like the idea of Moon getting both Rowlet and Popplio since Moon is a archer and Decidueye is a archer as well. Also Moon is a nurse and that fits with Popplio since Primarina is a healer.