besides, adoptive relationship

while adoptive relationship can be terminated, how are you going to terminate your relationship with your natural parents? You think the law will allow you to have both natural parents and adoptive parents?

Even if the US immigration law does recognize your "adoption" in the past, the minute you derived your immigration benefits from your natural parents, your adoptive relationship would have been terminated (the only reason you can immigrate with your natural parents). How would you petition for adoptive parents when your adoptive relationship no longer existed?

You don't need a lawyer, just use your logic.