SiaSL - No - but we do expect that he lies somewhere on the spectrum. It's just too hard to tell at this age how much.
The part about asking 20 times for the smoothie sounds like a toddler with AS; a brain that is stuck on one idea and can't be dissuaded from thinking about it even though being stuck on it is not getting him anywhere. (And you are right to make the stuck-ness not get rewarded; it just makes it worse.)
I think you've mentioned neurodiversity, so you might not want to go there... but from my point of view, if you think he's on the spectrum, getting professional help might be really useful in improving his coping skills, and getting him to be more able to move on from being stuck (very important skill).
We got a late start (dx at 5; I would have loved to have had help at the toddler stage) but we have done very well with an eclectic, non-rigid form of ABA therapy. It also incidentally trained us to be the kind of parents DS needed. Speech therapy for pragmatic language can also be really useful at this age; it's harder to catch up these skills later.
If your DS is on the spectrum, a lot of things that everybody else seems to use in their parenting will probably *not* work for him. For my kid, time-outs were a total disaster and 1-2-3 Magic even worse. He didn't have the self-calming skills that most kids have. Those skills needed to be taught and reinforced first. So from my perspective, advice for general intense toddlers may not work that well for an intense toddler with AS.
You're right that a lot of it is about what we're willing to do and how far we're willing to go. There has been a lot of compromise lately to avoid meltdowns. "We can't make a smoothie yet, but you can help me clean the broccoli and put it in the steamer."
I wouldn't call that a compromise, but rather skilled redirection. As long as you're not giving him what he's melting down over, I think there's a place for this strategy in your arsenal.
Maybe the most consistent rule in my house is "if you scream or whine for something, you won't get it." But if I can help DS not think about the thing he's after, what he's learning is that his brain is more flexible than he thought, and he can make his brain think about something else. That seems a pretty positive lesson.
DeeDee
