Any parents of multiples (different or same age), adopted children?

I'm thinking of in a couple years adopting a child from foster care/group home that's either a baby that can breastfeed while I'm still producing.. or a a child my daughter's same age. (She will be about 2yrs old by then) or a child older than her.

I have lots of questions and lots to learn but this is mainly to ask what is a good age in your opinion? (Obviously any age has difficulties and awesomeness). Also we may randomly have our hearts stolen by an adolescent or teenager!

I mainly want a child that can still grow up at a close age with my girl. (Shes 10 weeks now)

Any advice or telling me your experience would be awesome. Thank you!