Readings for Three Adopted Kids

Question:
The question is about our kids, not me. We adopted 3 siblings who all had different last names. When they found out they would have the same last name, they asked if they could change their first names. Well all 3 did change their first names. We don't know the middle names of the kids, but do know the first and last names on their old birth records. Do we use their old names or the names they now go by? We did let them choose their first names. The kids were not related to us, they were our foster children. We fostered the youngest, then found out he had 2 siblings in separate group homes. We then were able to bring all 3 together. Then fell in love with them and adopted them when parents rights were severed. Thanks so much.

Answer: (Responses to questions rely on the accuracy of the name and birth date provided with the question. Typographical errors or incomplete information can result in an incorrect response.)