Ann, to answer your original questions, what you describe sounds totally normal to me for a 2 y.o. Uh, lol, two of my kids have SPD, but even my fourth child, who at 21 months is very easy, "low maintenance" and happy, and has no hint of SPD, gets frustrated and starts calling out for mommy about a split second into any difficulty. And even he likes things done a certain way by me, and yes it can be tricky figuring out what that is.
I'm so busy with the others, and just plain lazy, that I often wait for the chorus of "mommy mommy" to get pretty darn loud before I go help out - and really only if I absolutely have to. Half the time he figures it out himself if he tries long enough. The other half of the time, well, either he moves on to something else, or one of his siblings helps, or he comes to get me (he puts his hand under my rear end as if to say, get off your fat ---, mom!). It's irritating when it happens every 5 seconds - those are the long days - like when he's trying to play with his older siblings' little legos and has difficulty taking them apart and putting them together. But generally I tend to think that a little frustration can be a good thing! So, my only piece of advice is to let your 2 y.o. experience that a little bit. Don't rush in to help too quickly. As for doing things a certain way to prevent meltdowns, I'd take that on a case by case basis - there are some things I'm willing to do (e.g. a very specific goodnight or goodbye routine, just so I can get out the door knowing they're not freaking out, because a good solid freak-out can last an hour or more; and if you do it wrong, like waving with the right hand instead of the left and without saying the correct words, you have to start over) but it's not great to let them have their way all the time even though that can make life easier - otherwise then you end up with my dd (long story! she's turning 7 y.o. shortly, and sometimes I still need to explain that I'm in charge of the house, and what I say goes, and I don't care if she didn't want me to move her stuffed animals off the rug so that I could vacuum - too bad; and if I want to wash her dirty laundry I'm going to do it whether she likes it or not; etc. etc.).
