To adopt or not to adopt? Help?

I have 2 foster children that I have to make a decision about adopting. I was planning on adopting but last week, was advised by the 10 year olds therapist not to. Then I consulted another well respected and trusted therapist and trauma expert today and she advised me not to adopt. She completed an evaluation on the children 18 months ago. The kids are 10 and 7. They have been with me for 18 months as foster children. I also have a 5 1/2 year old that I have adopted from the foster care system. She has been with me since she was 7 weeks old. The 10 and 7 year old experienced a lot of trauma. The 10 year old (boy) refuses to talk about anything and avoids emotions at all costs. He has an IQ of at least 117 (he refused to continue with the testing but the psychologist said it was at least 117). He has severe anxiety and hyperactivity. I can manage his behaviors at this age but it is difficult. So far, he is not violent with me. When he first came, he would get in fights with kids at school but hasn't in the last 12 months. He is not attached to me but the therapist feels that he has the ability to attach, it will just be extremely slow. He was the parent in his birth family (even though he left at age 7) and his mom described him as "my best friend". She desribed telling him about all her problems and keeping him up until 3 am discussing her problems. He has a tremendous difficulty allowing us to parent him and his sister. He generally gives in and allows it but if he doesn't agree with something, he really digs in and becomes difficult. At this age, so far I have been able to manage it but I don't know about the future. Recently, we had to tell him that if he refused his medicine and therapy we would not be able to care for him any longer. He gave in and took it but this approach will only backfire when he gets older. We didn't know what else to do though. The 7 year old is also manageable now but I actually have more concerns about her than her brother. She is totally a victim and a "doormat". She was sexually abused and has acted out sexually against my youngest daughter at least 2 times. She appears attached to us but in a heart beat would go to someone else who promised more things or attention or whatever. Within seconds of meeting someone she is touching them to the extent it makes people feel uncomfortable. It isn't sexual but it is not within normal boundaries of interaction. She will gladly tell anyone and everyone her story of abuse in order to solicit sympathy and adults really feed into this. She is learning disabled (as is my 5 1/2 year old). She is also in OT/PT. Finally, the experts are seeing what I have been telling them for 18 months and are saying that she needs a neurological evaulation and that something significant is wrong with her. She has no muscle tone, can not deduce things (like problem solve, think through what consequences might be, complete home work), looks dissociative at times (gets lost in a ranch house, says I thought we were going to buy something as we are walking to the car behind a cart full of bags of items purchased at wal mart, forgets what was just said, etc). She tries to be the good quiet child and will attempt to appear that way at all costs even if she is caught in the middle of doing something wrong she will adamently deny it - and forever deny it. She never takes responsiblity for anything that could be perceived as negative. Everyone that sees her talks about how cute and quiet she is, but when no one is looking she can act very vindictive and mean. Professionals are telling me that the feel that I am placing my youngest child at extreme risk if I were to adopt these kids and that they will become very disruptive. With the 3 kids, I already have aminimum of 6 doctor, therapist, psychiatrist, OT/PT appointments per week. I am very overwhelmed. I don't know if I can handle it if they are what the professionals are predicting they will be. But today I can handle it. Tomorrow I can handle it. So, when do I draw the line. Can we be a successful family? Or, do when end up creating a child who would have never been abused or neglected looking like an abused or neglected child because of what these other 2 kids might become. If we wait until they "disrupt" placement, then we might have unnecessarily delayed adoption for them and they might get to a point where they might be unadoptable, in addition, if the placement disrupts then we will all have experienced whatever trauma that caused the disruption as well as the after effects. I am just so lost at what to do. It is hard when they are this young. I want to believe that stability, therapy, etc will help them so that we can all be functional. The therapists say that the 10 year old has a better chance than the 7 year old because her intellectual capacity or processing capacity is so low. One thing I know for sure is that I would have never taken these kids in if I knew then what I know now. I would never have taken the risk for our family or daughter. But, now they are here and have been here. My daughter is attached to them so it will be painful for them to leave. (they aren't really attached to her but it is more because they have attachment issues or attachment disorder). Please help!! Tami