Sarah, I emailed one of my best friends who has two adoptive daughters and this was her reply:

OK---I am a nut about kid gifts! Love gift certificates for the zoo, children's museum, aquarium, children's theatre, etc. ! I can think of lots of things to get the boys, but sounds like their parents will be able to provide all the home toddler things.

Subscription to Adoption Today - not sure of name now---used to be Adoptive Families. You can find it online & they will send you complimentary copy, but I still read them & my kids are much older!