When our daughter was placed with us a friend offered to throw a baby shower. Since it was an unknown birthfather I wanted to wait until we knew for sure she would be staying. Then, we found out we could probably finalize at national adoption day, which was only 3 weeks after she was legally clear. Adoption day was on 11/15. (Hey, today is our 2 year anniversary of finalization!!!) We planned a party for 11/16. If we weren't able to finalize on the 15th, we would just have it be a baby shower. If we could finalize on the 15th it was an adoption party.
We had about 25 people. We did a brunch with crepes and eggs florentine and bunches of fruit and cakes and other brunchy side dishes. I hired a professional photographer and arranged that people could purchase photos of their families so we did a lot of family portraits. The final photo was everyone standing on the stairway with me, my husband, and our legally forever baby at the bottom.
By the way, for me adoption day didn't take away the fear that someone could still take her. That happened when we got the birth certificate a few weeks laer.