Hi OP,
my sister adopted my nephew nearly 7 years ago- he was around a similar age as the little one your friend is adopting. We gave her an adoption shower, with her knowledge and consent. Firstly because it was a way to celebrate what had been a long journey to parenthood, and it’s what was done for every other expectant mum in our family, secondly, it was also a way to have a few people to celebrate and have a nice time before the little one came, as once children are placed, rightly so, adopters cannot have guests for a while as the child settled and builds attachment, cannot go out to socialise etc, so it was a way to celebrate with close friends and family she was not going to see for several months, maybe longer as they settled and prioritised the child, and for my sister to have a laugh and relax a bit during what was a very stressful time, before he arrived.
we held it just before introductions, but after they had the confirmation of the placement via matching panel and agency decision maker’s decision was ratified, this means we didn’t it have long to plan - we planned it in a couple weeks, and didn’t give much notice (which was probably better as many people couldn’t make it, so kept numbers down.
we kept is very small - it was in my mums living room, we decorated with blue and white balloons but avoided “it’s boy” decorations as these has connotations of birth etc. we only had women and girls in the family, a a handful of my sisters best friends. About 9 or10 people including my sister, and a few kids.
We played a baby and toddler related quiz - anything from names of celebrity babies to peppa pig and in the night garden characters to historical facts like when was the stroller invented etc and we made it a bit fun like the teams had baby/toddler toys as a buzzer, team names were related to a kids show.
We did guess the childhood pic. - but we asked for no newborn pics - so people brought pics from when they were older babies, toddlers and small children.
We also did guess the baby food (other boring mumsnetters snarl at this but we had a good laugh, and my sister found it hilarious)
We did guess the theme song and characters from toddler, CBeebies shows.
people gifted my sister nappies and clothes for his size (she found out sizes from the foster carer/ social worker) and a few toys.
my sister enjoyed chatting and laughing - but one thing to be wary of - a couple people did insist on asking inappropriate questions about my nephew (as with adoption, much information is rightly confidential) so my sister and me and my mum and other sister had to have a plan, and very rigid about sticking to the line, this is about celebrating his future with our family not talking about his past.”
My sister also chose to reveal his first name at the shower, but this was her choice, and other adoptive mums may not wish to do this. We did not show any photographs of him.
hope that helps