If you’re worried, don’t ignore those niggles in your head. My daughter was similar to your son age 2 (except the lining up) and some things are still similar now at 3.5. She scored low across the board at her 2-year review last year and is on the waiting list for an autism assessment.
My DD could clap and wave since turning 9 months old (waving was only ever prompted) but she stopped waving soon after turning two. She is still non-verbal, no functional words or animal noises etc, can’t point to things in books, limited understanding of receptive language.
She hand-leads and brings us her empty cup/plate/bottle if she wants more. She’s never pointed. In hindsight, her eye-contact seemed fine with me (although this has now lessened) but she avoided it with others.
She has always been very active, doesn’t consistently respond to her name but can be quite affectionate with me. Role-play/imaginative play is limited.
Maybe try speaking to the nursery SENCo, just mention your concerns and see if they also have any. No harm in asking a health visitor for advice, although they may tell you to wait for the 2-year review.
in my experience, if there are concerns it’s best to get the ball rolling as soon as possible as we’ve had endless back and forth and delays with referrals.
I started raising concerns about my DD’s speech delay two years ago and raised concerns about autistic traits one year ago and only recently was she placed on the autism assessment waiting list.
I don’t want to worry you further, just wanted to share my experience as I had similar concerns but doubted autism and so did family around me but looking back there were other signs too that perhaps we had missed earlier.