I wouldn't worry to much right now, all he needs to do when he starts school (in 10 months time!) is go to toilet independently, put his coat on & off, put his shoes on & off, feed himself his lunch and follow instructions (sit there, don't play with that etc).
With the follow instructions, you'll probably find that he will do this better for people who aren't his parents (does he do it at nursery etc?).
My DC in year 2 goes into school in her pe kit on outdoor pe day as its so much easier for them not to get fully changed, but can easily manage to do shorts & t short for indoor pe - but still insists on me getting her changed for school every morning but that is because she's lazy but can absolutely do it herself when she has too. Your dc might be the same.
As long as your ds can do the above, I wouldn't worry about grouping things together etc as he will get there when he's at school & I doubt my dc could do that this far before starting school too.
My dc started school having never really drawn anything, couldn't wrote her own name (but could recognise it), couldn't read anything and that is completely normal as all she did at nursery was play outside, run, jump & explore - she was never inside & couldnt sit still at home at all. 2 years into formal schooling and her reading is above expectations, her writing is fantastic & she is a whizz at maths.
They all get there in their own time & so long as he can manage the basics when he starts I honestly wouldn't worry.