I have a 16yo who had glue ear from a baby (and three lots of grommets) and was subsequently diagnosed with ASD too in his early teens.
What I'd say is the behaviours you've listed are normal for a 17 month old. Hand flapping, for example, can be a normal up to around age 5yo.
Ds had and still has good eye contact, babbled better than either of his sisters, and talked quite well (although not as well as his sisters).
He didn't line things up (other than cars in a queue), order things - he did like spinning wheels (working for Kwik Fit was apparently the height of desire for employment), but not in an obsessional way, but nothing that stood out.
With ds I was told repeatedly from various medical people that some of the symptoms that point towards ASD, also point towards glue ear. That meant that they weren't happy to assess ds while the glue ear was still an issue, unless there was more to it than what I could see.
Now as it turns out, ds does have ASD. However the behaviours he had at 5/6yo which made me wonder, were also glue ear markers. I also found that people used "he's a summer boy; he'll grow out of it" a lot, which makes me suspect that some of the attainment difference is simply that reason-summer boys get dismissed as "growing out of it" when they do need a bit of extra help.
What triggered me going to the GP and asking for an assessment, was nothing that I spotted at that age.
What I can look back and say is things that were just "his little quirks" were signs. Things like he disliked the feel of sand so much, even as a baby, he wouldn't go off the blanket on the beach. He wouldn't wear trousers (even at 16yo he rarely wears anything but shorts, even to school). He was both sensory avoiding and sensory seeking.
For ds, he was initially referred (by me) for ADHD. At the initial assessment, they pointed him towards ASD. Once he'd got that diagnosis, they wanted to relook at the ADHD one. Both of them they concluded the assessment by telling me that he was very close to the diagnosis line. He'd either be "NT with ASD/ADHD traits" or diagnosed with them. You may feel it is odd, but I had such a sense of relieve when they decided he did meet the diagnosis criteria. It wasn't for me, it was for him; it really helped him understand that he wasn't just the "naughty boy". It's done wonders for his self-esteem.