The most illogical track of YHM

One of the most illogical track of YHM track was how they show Adi and Alia Marriage... First they show Shagun Adopted Alia legally and then give custody of Adi to Ishita..... Isn't it after adoption....Alia because Sister to Adi because Adi Bio mother Adopted her.... Is that possible for them to get married after adoption?????