Sensory issues would be:
Seeking out sensations or avoiding sensations of five senses plus vestibular ( balance) and proprioception ( knowing where your body is in space)
Could show as:
Bathwater temperature being luke warm
Leaning a lot on other people
Not liking bright lights ( may show as behaviour)
Seeking out strong tasting food or not liking certain textures
Liking spinning things eg liking to watch the washing machine or flashing lights (me)
Liking tight clothes, or soft clothes or hating labels or seams. ( With mine I didn't spot that so much as to me it seemed normal... But apparently not)
Chewing on stuff
Calmed by being under a heavy duvet
Startled by loud noises. ( Different to others)
I just noticed in your list you mentioned things the school wrote on dd's assessment form whilst also claiming it was solely a parenting issue. It was these things that the assessor pointed out as should have raised concerns to the school.
Schools might not notice anything wrong, they are not experts, a lot of signs are subtle.
DD seemed neurotypical until about aged 9. Yes quirky, yes signs but not enough to trigger visiting the GP, compared to her less subtle sibling.
Some early signs I only remembered as I was filling in siblings assessment...eg not waving, not being asked to be picked up etc. When a baby.
It might be worth looking at yourself too. Looking at dd's assessment stuff raised yes but that's normal in me ...ahhhh heck.
Guess who is also going through diagnosis assessments!
even if not it it is worth looking at to be able to get a clear picture of your kid. Eg I didn't recognise some of their sensory difficulties as they are normal for me but not normal for other people.
The three updated areas of difficulty are:
Sensory
Routine
Social communication.
Waiting lists are long so if you have worries, look into it to see if you want to ask GP for a referral before the gap widens between peers.
A diagnosis doesn't change him, or you, or me, but does give legal protection and he will benefit from extra support in future.
Of course, there might not be a diagnosable condition. Only you know him well enough to see. Sometimes it does not become apparent until they are older, or difficulties will resolve as they learn new skills and catch up.
You can't tell from a couple of posts on the internet! Just that some things sounded so similar to DD.
On the plus side: DD found her tribe at secondary and was mothered at primary. (Your Ds sounds similar)
Ds has mates at school.
Both autistic.