Hi there, welcome!
Wow, you have a special family. I too adopted my son about the same age from foster care. He did not have the same level of trauma your son has, but he did have pain from a brain mass which complicated things (then had brain surgery at age two years three months.)
I understand not wanting them to use their history as a "crutch" in terms of them reaching their potential and not being destined to be a product of their early experiences.
That said, if a child has genuine neurological damage or changes then they perceive the world in a different way. Parenting them requires so many different methods, and those of us who have been down your road will tell you, typical parenting methods just do not work well for many kids.
My son like yours has a complicated group of things going on. Mine has cognitive delays that yours does not but he is on the spectrum (you say they suspect that for your son) and he also has attachment issues due to his early history.
As you know from being a mom....especially now a mom to a child you had from newborn age on.... a person's core ability to trust and how their brains are wired is established from pregnancy on. Baby has needs, cries, mom (primary care giver) meets those needs, baby develops bond and trust, and on and on.
Abuse affects people at any age but when it happens from birth to three years of age it can create permanent structuring of the brain to not be able to securely bond. This, like autism is on a spectrum from just being insecure in bonding to being really unattached and not having any ability to care about others feelings. It is a real thing, a brain injury of sorts, and not a choice. Drug exposure can do permanent damage too. ODD often implies to people that kids have skills and are simply choosing not to use them. When you can find out what is driving the ODD like behavior, then you have a great place to start. And you are right, time outs, rewards, consequences do not do the trick ....usually because fundamental pieces underlying being able to perform those tasks are missing. THEY dont know that though. So they say they just dont want to. AND they have heard they are naughty for so long.....they start to believe it. Our kids live every single day being corrected for their negative behaviors. It doesn't matter if we are amazing and provide tons of positive....you can imagine how it tears them up to have teachers, staff, us, siblings, peers angry with them over and over through the day.
Unfortunately spectrum symptoms and attachment disorder symptoms and drug/alcohol exposure symptoms overlap and it can take some time to sort it out. Some kids are labeled autistic when it is really their Reactive Attachment Disorder (RAD) symptoms and vice versa. Others, like my son, actually have both As time has gone on it has become clear that the dominant issue is the neurological disorder....the autism and the brain injury. (make no mistake, Reactive Attachment Disorder (RAD) changes their brains and the effects can be just as permanent) Either way, our kids actually do not see or feel the world as others do. It is usually all about them, and their immediate gratification. Not to be purposely selfish, but because that is how they are wired. They need specialized techniques to learn about how their behavior impacts other people and the connection to positive and negative consequences.
Therapists and behaviorists who are not specialized in attachment or autism can do more damage than help so if you think that this could be part of the issue then it is really important to find a center that specializes in reactive attachment disorder. One by us works with kids who have both autism and Reactive Attachment Disorder (RAD). Even if it is from another state, they can help refer you to other places.
You have tried all the right things, all the things that typical parents try and still he has issues, and no kid really wants to be in trouble all of the time. At this point, it makes sense that he does not have the insight or vocabulary to say..... Mom this is just overwhelming to me, I get lost in tasks that are just too much. My son says "I dont care" and "Good, I want to do it wrong" and "I dont want to" and it is clear that he truly does not have the ability for some things. We have to give them the benefit of the doubt.
Just a thought....I'm topic jumping here, sorry..... You may have done this but you could try to put pictures of the types of clothes that belong in each drawer/shelf on the outside of the drawer? Have two baskets, one for dirty clothes and one clean. If they dont make it to the drawers/closets etc....then he can dig in the basket.
Have you ever read the book "the Explosive Child"? Its by Ross Greene. That can be useful too to help come up with ideas for working out solutions to lack of skills and discipline.
It can really help to go to a neuropsychologist to help sort through what some of the true issues and diagnosis are. Their job is specifically to look at his developmental history and behaviors and to connect what he is doing with how the brain works. They look at both neurobiological conditions as well as mental health issues. (if you go to only a mental health provider they often only focus on mental health conditions). I know you said that they are looking at other assessment etc....but if not a neuropsychologist or a team approach (like a developmental pediatrician/Occupational Therapist (OT)/Speech language Path/psychiatric/etc....) then often kids are labeled as ADHD plus ODD plus Anxiety....sometimes mood disorder. This can be legit for many...but with your son's history a deeper look would be really helpful I suspect. We only have a short time to do this right for them. It can be a real fight to get to the bottom of things. childhood flies and the thought of a miserable time for him and for you is so unfair, you have given your heart and time to do a great job, I pray that the people working with you can really give you answers and tools.
I can totally relate to your son's behaviors and how hair pulling it is to have them use such disrespectful actions and words. I still struggle not to take it personally and to realize it is a limitation of his ability to process and function in the world as others do. It is intensive to sort through different ways to help them learn to be responsible and you are right it is very important. Just that at this point you do not really know his limitations and skills and he is screaming that for some reason it is just too much right now. I'm NOT saying give him a pass, but you may need to actually put one shirt in while he puts the next then you the next etc....and yes, you have other kids but he will take more time. It is what it is. He will learn to do it and if not, as others have said, there will come a time when you have to decide if you are going to let that be a big power struggle or if you are going to prioritize things like the aggression as bigger issues to work on.
here is a site that I like for helping to understand attachment disorder in case you feel this may be a part of it (and from his history, it is quite likely on some level). It was started by parents who adopted from China but the trauma and bonding history has the same impact no matter what country this happens in. They now have parents from any adoption situation part of their site and board. (they have a discussion group through yahoo you can sign up for through their site...much like this, moderated though and not viewable by the public)
www.attach-china.org
There are other nice sites too. Just do a search for Attachment Disorder or Reactive Attachment Disorder...BUT do not freak out at some of the extremes....there is a range of severity.
(like some kids are cruel to animals or abusive to siblings or start fires, etc. My son was obsessed with blood and gore and as we worked on things those obsessions are gone.)
Sorry this post is all over the place, I wrote it while helping my son get ready for the night. I hope it makes some sense. I really get being lost in this. I have ONE and it is hard.....you have other children who are just as important. But in any family where there is a child with special needs, it is just the way it is, they need far more time. I know you live that every day.....it must be very challenging.