We have a trans-racially adopted daugher (8) and are in process of adopting again. We've been told the Sesame Street Book, "We are Different, We are the Same" is beneficial to younger kids. We also have a relationship with a woman who was adopted & had multi-racial adopted siblings. She has encouraged us to make certain our daughter can survive in 'their' cultural world, as she gets older. She mentioned cousins who were adopted from Korea & never experienced anything Korean, had difficulty as they got into the teen years. She said her parents exposed the kids to many cross-cultural activities.
It's our goal & not nearly as easy as some make it sound. The questions from our daughter seem to come in waves. Started much earlier for us 2-3, K was a big one, then this past summer again.
Good luck...it will pass, you will make it through!!