This is my first time visiting this forum and I was relieved to find this thread...my little guy is definitely high needs and definitely fits many of your descriptions. He has been alert and active since birth (now seven months) and whenever we go out, everyone comments on how cheerful and smiley he is. But he is the screaming-est, screeching-est, moody-est, little baby I have ever known! We adore him and feel so lucky to have a healthy baby but it has been HARD! Struggled with colic and GERD and breastfeeding difficulties from day one but the reflux is almost behind us and the breastfeeding got a lot better. No more endless hours of crying inconsolably but now it is just needing constant attention (lasts about 60 seconds alone if I'm lucky and is quickly bored with toys and any kind of jumper, bouncer, etc.)
Being out helps and routine helps and doing whatever i can to keep him rested helps. But he is so moody that he'll be happy in the carrier one day and screaming to get out the next-resulting in a loooong walk home carrying a 20 lb baby in my arms. I've definitely been the mom of the fussing, crying, screeching, squirming baby in every group I've been too. So, as much as I don't have any advice to give, it is nice to find other mom's out there going through the same thing...