That sounds pretty like my 2.7 y.o. in some ways, and I have no concerns about him.
~ He knows the alphabet: letter names and letter sounds. He can sound out some short words & can sight-read and spell quite a few words.
~ Counts and understands concept of counting. Can take a number and add one. Recites numbers to 200 in 1s and 10s, recites multiples of 100 to 1000.
~ He knows shapes and colours, including unusual shapes and shades of colours.
~ He's very observant.
~ His language/memory is good. His diction is poor (referred to speech therapy for this) but sentence structure is more like the average 3+ y.o. He asks what words mean, where they come from, extrapolates from known words e.g. guesses that Watford means the ford over the river Wat since he knows the meaning of Bedford and similar names. If I use a word which has 2 different meanings, he will tell me about the other meaning and ask me to explain the difference.
~ Knowledge-wise, knows lots about pregnancy, seasons, days, dates. Could tell you that leaves go brown and fall off trees in autumn, but that beech hedges keep their leaves on all winter till the new green ones grow in spring. He can correctly use terms like vertical & horizontal, clockwise & anti-clockwise, 90 degrees, body parts. He can describe how the digestive system and circulatory systems work.
~ Often remembers things, such as conversations or objects in another person's house, from months previously (despite not having talked about them for months). I am constantly amazed by this.
~ Loves being read to, and will 'read' his own books happily for quite a while. Just starting to make up his own version of stories.
My DS can't:
~ He can't jump with both feet off the floor
~ Running isn't very fast, and he's reluctant to do it unless there's a train at the end, or or it's in the supermarket.
~ Okay at climbing but is generally fairly cautious at climbing outside of the house.
~ He can't put his own clothes, and can't take them off either, though he is making progress with socks. He shows no interest in doing so, and never has. I asked on MN about this here and was told it was pretty early for a child to be able to start doing this and not to worry. He can undo shoe straps but nto take them off.
~ We do EC and have been pottying him since 8 months. He has been in trousers rather than nappies indoors since 18 months. A wet nappy still doesn't bother him at all and he won't tell me he's done a wee when he's wearing a nappy, even a cloth one. He won't always tell me when he's done a wee in trousers, although he usually will if he's done enough for it to go on the floor!
If your DS is reluctant, you could try looking at the UK EC site for ideas - the focus is on helping your child be aware of their toileting needs rather than potty training as such. FWIW, I only know one other person IRL with a similar age child who's actually started potty training.
~ DS is a bit interested in colouring. He holds the pen in his fist. He does try to draw things, but only trains. He doesn't draw for long as he gets immensely frustrated when it looks 'funny' (ie not exactly like the real thing). If we draw or write something a bit 'funny' he will complain about our drawing too. 
He can draw straightish lines and have a go at circles.
~ DS doesn't like being with other children, and sees them exclusively as a threat to his personal space / to his possession of toys. He has never spoken to another child other than to tell them to go away or leave his toys alone. "Get rid of that boy! Not come here! Somewhere else!" would be a typical example. However, he's starting to be interested in other children and will ask me why they're crying.
He has had separation anxiety since 7 months which means he's been terrified other people other than DH and me. He is now sufficiently confident with adults that he'll occasionally talk to people he doesn't know, but that has only been in the last couple of months. He won't be left with anyone other than DH, me, his grandmothers or one grandfather (and that only as long as his grandmother is around). In a group context he follows me round closely, even if I'm just walking to the other side of a small room (and have told him that's what I'm doing), as he panics about being too far away from someone he knows.
I have no fears about autism as he is very good at 'shared attention' with familiar adults, and clearly has a fairly well developed understanding (for his age) that other people think in ways that are different to him.
Both DH and I were children who weren't particularly interested in running around or 'physical' things, and preferred to stay in one place doing more sedentary activities. Both of us are 'academic' and not particularly sporty now. A lot of DS's interests reflect mine (unsurprising as he spends all day every day with me).
DH apparently didn't speak to another child until he was at least 4, and at the age of 3.5-4 would only grunt at playgroups when spoken to by either an adult or children. At that age he didn't 'play' alongside other children at all, but would only do cutting & sticking. He is now a well-adjusted man who does managerial / people-skills type work. :)
Sorry, that was an epic post. 
I wouldn't be worried about your DS, just give him plenty of opportunities to practise those physical skills. My view is that some children are interested in running around, some are interested in less active things. I think it's unusual for them to be equally good at everything.