Wow does your post bring back memories!
My mother who had raised 8 very intelligent children and had 10 other grandchildren before mine was born was startled by how much my child DELIGHTED in problems (making or witnessing them). She coined the term Mr. Mischief for him somewhere around the current age of your son. He soon picked up on the term and truly delighted in it too.
The part I most tuned in to in your post was the laughing at discipline. This was an important sign for us. It is very early in your parenting career at this point so you may not follow the same path as we have, but that was an early sign for us of our son's ADHD. It is frustrating, frightening, and sometimes infuriating when your child responds that way to discipline.
We recently read a chapter in a book on ADD titled "ADD Games". One game was called "Let's Have a Problem". The chapter talked about how in order to regulate themselves they unconsciously create conflict just to feel a "normal" level of stimulation. We related very much to what we were reading. Additionally, I learned that one of my husband's brothers had also been like this. The one diagnosed as ADHD as a child. I have spent many hours commiserating with my MIL about the challenges of parenting such a child and I have been very thankful to have somebody else who truly understands.
My experience has been of a HG+ extremely verbal hyperactive child who needs less sleep than I do and is highly amused at finding anything that evokes a negative response. It is incredibly exhausting and way more than most parents could begin to relate to.
With a child like this, as others have mentioned, it is CRITICAL to remain very calm. If you lose your cool you are "feeding the beast" so to speak. It is providing the (negative) stimulation your child is hungry for and it is as addictive as a drug because in his brain he is getting the shift in neurotransmitters he needs from that reaction. This has been the number one thing I have been told by the experienced parents and professionals I have consulted.
You won't be able to be perfect in this. You will have such moments of extreme stress that you will not remain so calm but every time you do maintain your composure you have helped avoid the pattern.
The number two piece of advice has been to make self-care a priority. You have an incredibly intense life and you need to have time to renew your energy because every day is draining and overwhelming. Don't let yourself be last on the list because other needs are too pressing.
A final thing I have learned that relates to your post is that the sleep issues you mentioned are common among kids with ADD/ADHD because they need a certain about of stimulation to be ABLE to fall asleep. Most kids are the opposite: quiet, dark, still. My child NEEDS to listen to complex calming music or watch TV and never totally dark. It's been interesting reading about this difference in many ADD children (and adults). And it's been delightful getting more sleep. I wish I had known about this years ago.
So that may be more information than you are ready for but I hope it helps and provides some ideas for you moving forward. I think being aware of possible diagnoses can go a long way towards spotting them and addressing them sooner before school impacts begin to really complicate matters.
