user1482528086 our son came to live with us at 3, almost 4 and was 4 when we had the celebration day.
It was a brief bit at court where our son and 9-year-old birth daughter showed no real interest in trying on the judge's wig or having their photo taken.
Our son was given a teddy and I had already bought a toy for both kids and given them to bring on the day.
We all dressed up and we went and had our photo taken, went to lunch and then went and painted pots.
All efforts to recreate the day have been stoically resisted by our son, who just wants to be one of the family.
The photos from the day are a nice reminder that we are a family of four, and we met the two social workers (who were great) and all showed up and met an unknown judge on a certain day.
It was a lovely day but I think that the weight of the day is the many years all of us spend getting to that point, so in a way, do exactly wha you want to do, invite who you want to invite, spend it how you like.
We had our son dedicated (like Christening about 4 months later and that was the time for family to celebrate with us).
Hope your day is exactly how you all went it.