Not sure if this will assist you but we completed two adoptions from Guatemala at two separate times and they are close in age in my opinion. Our oldest is 2 years old and our youngest will be 10 months old on the 8th of Apr. They get along great and we will never regreat our decision to adopt two children this close in age.
When we were in Guatemala visiting our princess no 2, we met a couple who were picking up two babies. They had taken a referral for a baby and then the birthmom took that baby back so they lost the referral and then the birthmom found out she was preg. again and the couple was once again contacted and their plan to adopt one child turned into adopting the child that they were initially referred and the baby that was on the way. When we met them, they were on their pickup trip and on their way home
So, what does this mean, yes people do adopt two at one time and for us two back to back adoptions