Polarbear, all hugs and advice gratefully accepted! To save space, I haven't quoted your extremely helpful post.
Yes, you're so right about googling. Nothing good is coming from that.
In a nutshell, I think you're right that the "answer" to this will probably unfold over time. I'm trying to disentangle what is probably normally developing EF and frustration tolerance from possible motor issues. DS has easily passed all his motor milestones up to his 3 year well child visit, and was early on several (dragged himself to my breast the night after birth; never crawled, started walking at 9mo; very early hand coordination for pincer grasp and tool use). But he has quirks that stand out, like the stairs--he'll only use his right leg to climb--and the arts and crafts refusal (while eagerly helping me build shelves or do woodworking).
What concerns me is the drop off in motivation in areas of previous interest, like the reading. If it's organic, that's fine. Passions wax and wane. I just don't want to have some physical impediment stymie an interest.
I think it's worth shopping these observations by his ped to see if she feels an OT or development vision evaluation is merited.
