Hello, [name]Lyndsey[/name]! I hope that you and little [name]Dash[/name] are both doing well 
[name]Raffy[/name] ([name]Raphael[/name]) is our biological son, and [name]Rosie[/name] ([name]Ambrosia[/name]) and [name]Jasper[/name] were adopted. I am currently pregnant with twin girls. [name]Raffy[/name] was our first child, but after [name]Rosie[/name] and [name]Jasper[/name]'s adoption he is the youngest. [name]Raffy[/name]'s two middles are old family names on my husband’s side, but to be perfectly honest, that wasn’t really the reason we picked them. With [name]Raffy[/name], we weren’t concerned with honouring anyone, partly because we knew we would have more children, and partly because I was very concerned that if we honoured one parent, grandparent, cousin or aunt, I would feel very guilty for not honouring the rest - and I have a lot of relatives, so poor [name]Raffy[/name] would have ended up with twenty middle names! I have always liked the name [name]Peregrine[/name] and so insisted we keep the tradition alive, and [name]Cyrus[/name] was actually a suggestion from the lovely [name]Susan[/name] here on Nameberry, as a middle that she thought would flow nicely - it wasn’t until we had decided on it that my mother-in-law pointed out the family connection to us.
With our adopted children, I felt that it was important to honour their background. I agree that choosing a middle which reflected their nationality would be a very good idea if it was an international adoption - I feel that a, say, Russian child receiving a fully American/British name upon their adoption wouldn’t help with any possible future crises of cultural identity. [name]Rosie[/name] and [name]Jasper[/name], however, were an in-country adoption. If they hadn’t already been three and a half and fifteen months respectively, and it hadn’t been clear to me that their biological mother must love them (it was a private adoption and we know nothing about her, but from the background information that I have gleaned from our social worker it is clear that they were in a bad environment and their mother was simply unable to care for them. Remarkably, though, neither have fetal alcohol syndrome or any drug dependencies, so in my mind it is clear that their biological mother was protecting them as best she could) then I may well not have felt that that link was important - your family is, in my opinion, the people who raise you, love you and know you, not the people who happen to share DNA with you.
Their names, when we were introduced to them, were [name]Baby[/name] ([name]Rosie[/name]) and Jontee ([name]Jasper[/name]). As we knew nothing about their biological relatives, their previous names were the connection we chose to use. [name]Rosie[/name]'s middle name is [name]Frances[/name], as this is the real name of “[name]Baby[/name]” Houseman in Dirty Dancing, and [name]Jasper[/name]'s first and first middle name are [name]Jasper[/name] [name]Theodore[/name] - the initials JT are a connection to Jontee.
[name]Rosie[/name]'s full first name, [name]Ambrosia[/name], honours three people - DH’s half-sister, [name]Amber[/name], who was incredibly supportive throughout my pregnancy and the adoption; [name]Amanda[/name], my best friend; and my mother, [name]Primrose[/name]. It’s also a mythological connection, which is lovely, as I studied Classics at university. To me, it was very important to honour these people this time around, but it was also important that [name]Rosie[/name] have a name which automatically connected her to family members. Especially as we also have a biological child, I was extremely anxious that she and [name]Jasper[/name] would feel completely part of the family.
[name]Jasper[/name]'s second middle is [name]Edmond[/name], which is also my brother’s second middle. Again, a family connection for him was important to me, but a large part in our picking [name]Edmond[/name] was the fact that we both love it … It seemed appropriate to honour my brother over my sister (who we are honouring this time around, with the twins), as he is the only one of us siblings who does not have children yet.
Personally, the family names I would choose to use would be names of people I or my husband have actually known, rather than names from back in the family tree, but I don’t see why names from back in the family tree would not be suitable for adopted children - they would gel them to the family in the same way as the names of living relatives would, although perhaps with slightly less of a personal connection, and of course once a child is adopted, they are part of your family, regardless of DNA - so YOUR old family surnames are THEIR old family surnames, too.
In some ways, I think it would be nice to give your adopted children a name which reflects their ethnic origins, or a second living family member name. On the other hand, it would set them apart from their siblings who are your biological children, which is something I personally would always strive to avoid, in every way. So, I haven’t really answered your question at all, and I feel like I have given you my entire life story and still been thoroughly unhelpful!
But good luck, and I hope that you get some good advice, as the lovely people here at Nameberry always give