I dunno! I think that much of what you've written sounds like an adorable and delightful 3 year old who is possibly quite bright, maybe gifted. OTOH, I see some red flags for motor coordination. What does his ped say about the motor observations?
To be honest, I suspect that for most of us with 2e kiddos, nothing was very obvious at 3. My ds has Developmental Coordination Disorder in a way that impacts his life tremendously, but I didn't see any of it at 3 years old - I just saw a cute bright kid who had a few quirky little oddball things going on like late talking, not "bothering" to crawl etc. DS also passed all ped "surveys" and well-child visits with flying colors even though in hindsight when he finally was diagnosed at 8 the neuropsych could easily pull a huge number of examples of delays in early childhood milestones that the ped never took notice of. I think it's really easy with high-cognitive-ability kids to brush aside any other concerns such as perhaps hand dominance or the way your ds is climbing stairs, so you are actually in a good place for your ds in that you are noticing and paying attention to each of these things.
Are they issues or challenges? It's quite possibly way to early to really know. Talk to your ped about them, maybe ask for an OT or PT assessment to look into it further. I wouldn't devote much energy to googling things such as NLD etc... there are so many symptoms that are shared between NLD/Autism/DCD/ADHD/etc, as well as being things that sometimes completely NT kids also struggle with. It's quite likely that the best answer to "what's up" isn't going to happen with one eval or in one moment or any time soon. For most of us with 2e kiddos, understanding what was up took years, and definitely took a step into the school years to see the impact of their challenges.
Brief summary: most likely, he's fine. You have some concerns, so bring them up with your ped. If you think a specific type of assessment would be helpful, ask for a referral (I'd ask for OT or PT referral). In the meantime, try not to overthink it. Let the professionals sort out what they can.
Sending you a big hug!
polarbear
ps - has your ds had a vision screening? My totally NT dd had some of the same issues you mentioned above, due to poor vision.
