Hello AnnaLCox,
Good thing your middle initial is written in big letters 
Anyway, I'm late to the party but I figured I'd offer you my perspective, in case it may help you or someone else reading this thread someday.
I am not an adopter but I've worked in a field related to adoption in Russia. Russia is closed to single adoptions, to the best of my knowledge, but it's still an exemple of what you might expect from adoption abroad.
I had access to the adoptions judgements of dozens of children and the recurring factor that led to them being in orphanages were as follows :
- alcohol and drug abuse
- violence (domestic violence)
- neglect (children inadequately clothed in flats without heating in very cold winters, inappropriately fed, etc)
Furthermore, the living conditions in Russian orphanages were not great, to say the least.
There was national preference for adoption which means a child could not be up for international adoption until they'd been on the local register for at least (I think) 18 months. Most of them as a result were around 3-6 years old when adopted internationally, sometimes older though children over 5 are "less desirable".
Children available for adoption had a host of health issues, global developmental delay especially but also other conditions such as hydrocephaly, etc. And probably FASD though I'm not sure it would have been reliably diagnosed in Russia.
I think it's possible for single adopters to adopt in Lithuania (don't have first-hand experience though), Colombia and (I think) Bulgaria ? Not sure. But most children there available to international adoption by a single parent will be :
- older
- adoptable only with brothers/sisters
- having significant health needs
You need to be aware of that and adjust your expectations before going down that route. Also, international takes longer. Local adoption in the UK is incredibly fast (1-2 years based on what I read here).
The truth is that the UK remove children from families much more easily than in other countries, which means there are a lot more children available for adoption locally than in most other countries and as a result it goes much faster. Waiting time in my own country is more like 5-10 years for local adoption...
So in terms of trauma and needs I don't think you'll get "easier" children from international adoption. If anything they'll need more help and support.
In terms of contact with birth family, I'm no expert. I do know that knowing where they came from, and often establishing direct contact, is hugely important to a large number of adopted children. That doesn't mean you are any less their parent. This is why, incidentally, I am not in favour of anonymous egg or sperm donation (and this is one of the reasons why I decided against donating, because in my country it is anonymous).
I know from reading these boards that contact with bio parents in the uk is not always very well maintained (but frankly the rules the bio parents have to comply with to write those letters are so stringent, I'd find it hard too ; especially as the letters are supposed to be addressed to the adopters and not the child themselves).