Hi, and welcome to the board.
A few of the things you mentioned are issues we've dealt with, with my 11yo ds who has Asperger's Syndrome (AS).
The eating too much and not feeling full has always been an issue for my ds. Because he always felt hungry, he'd get very upset if we told him he'd had enough food and to stop eating. When he was your dd age, one food incident that stood out to me was he'd eaten in one meal nearly 1/2 pound of pasta, a sandwich, several servings of fruits & veggies, drunk a quart of water and was still starving. I made him wait an hour to see whether he'd start to feel full, but he didn't. He just counted down every second of every minute of that hour and then began begging for food again.
We tried ADD meds for my ds ADD. The meds didn't help his attention deficit, but it REALLY helped his over-eating. He no longer felt hungry. In fact, he used to sometimes forget to eat, and I'd have to remind him, or he'd get too grouchy from not eating. The doc has permitted ds to stay on the meds for the eating issues. Unfortunately, the meds aren't working as well as they used to, but at least now ds is old enough to reason with a bit better about portion control.
The volume control is another issue we've had to work on with ds. The speech therapist helps ds practice speaking at different volume levels, and now we just prompt ds to speak at whatever volume he should be speaking at (volume 2 in the house, volume 3 when speaking in front of his class, etc).
My ds also has low physical stamina. In kindergarten, it would take him about 45 minutes to walk 1/2 mile home from school, stopping several times to rest. As he got older, he used to always complain about his ankles hurting when he walked. The orthopedist couldn't find anything obviously wrong with ds legs/feet, tho' he did find a slight over-pronation(sp?) when ds walks, which orthotic shoe inserts may help. Insurance won't cover the cost, so we haven't tried the $500 hard-shelled ones. We did try the $75 temporary orthotics, and they helped a bit. I'm not sure how much of ds low-energy is due to his body not feeling good when he's active and how much is just due to his being low-energy. We've continued to encourage physical activity, and ds has built up stamina over the years. He actually sort of enjoys it now, but he still gets sore ankles and has to take breaks.
Since autism spectrum disorders are so common nowadays, I wouldn't worry about the label, esp if getting a label can enable your dd to qualify for supports she wouldn't be able to get without the label (supports at school, therapies through insurance, etc). My two AS children (also have two "neurotypical children) didn't get diagnosed until they were 8 & 12yo.
If you choose to pursue a formal diagnosis either now or later, you can seek a neuropyschologist or developmental pediatrician for testing.
I'm not as active a participant on this board, but this board has definitely been a big part of my AS education and survival over the past few years!
I'm new here as well, but wanted to jump in. I'm going to throw a few non-ASD issues at you.
Some things that stand out are her sleeping issues. My first
Thank you all for your thoughts and advice.
I just want to welcome you too and tell you your dd is Gorgeous!!!