I think, personally, that once you have established the diagnoses and other facts, then if the situation is as serious as currently indicated you would want to know that you have clinical psychologists and psychiatrists who specialise in developmental trauma within physical reach (ie it depends on where you are in the country) and that there is package lined up in terms of cost. I am not sure how easy it is to locate such people now - I found it really hard to find anyone when my dc were young, but recently a practice called Beacon House near Brighton (I think) has been linked here. The key thing is funding for you, as I understand that before placement your negotiating position is stronger (awful way to look at it, I know!!) and if you post about that specifically you may well get some very focused advice!
In the past, RAD was diagnosed and seen as a lifetime sentence, but I think that the situation is different now, greater neurological understanding has given more insight and in relation to trauma and attachment therapies have moved on, it is a matter of accessing the right expertise, and research shows that many children who have suffered trauma from neglect can go on to do very well with the right support.
However, it will be a huge investment of time and energy.
Having said that, the children will also be little people in their own right, aside from the problems, so if the match was right it might well be perfect for you and it would be a matter of getting the right supports.
In relation to therapy, I have just posted this on another thread so it is on my mind - you might find it helpful - it is 25 mins long. I don't think the behaviours are referred to as "controlling" anymore incidentally but I might be wrong:
www.youtube.com/watch?v=jYyEEMlMMb0
Trauma is not a static condition, as per the video (see Bruce, towards the end) and things should get better and better over time.
@nikkibahm please don't be put off, there is room for lots of different opinions.