Well, first off, a 2.8 year old is not old enough to be solely responsible for brushing his own teeth. He just doesn't have that ability yet. It's great that he's doing it on his own, but if you want his teeth to actually be clean, you probably need to do it again afterward. We did it that way (two steps - one by child, one by parent) for a long time.
How verbal is your DS? Does he tend to understand everything you say to him in general but just not get the choices conversation? Or does he still miss a lot of what you say? If he doesn't have great comprehension yet, you can still use choices; it will help him learn, but it will take longer, so be patient! If he does understand you well in general, then maybe you could try sticking more closely to what MSK said. For example, with the nursing/bathroom thing, you're setting up a situation you don't want to follow through on. So don't set it up. As another poster said, it's basically a threat anyway. A real choice would be the pull up one she suggested or perhaps would you rather go to the bathroom before you put on pajamas or after. Then if he doesn't decide (some people count to 10 to give a reasonable amount of time - up to you!), calmly make the decision for him, and carry him to the bathroom if needed.
For cleaning up, I would never expect a child of that age (or even a 3.8 year old) to do it all by himself. I wouldn't even offer a choice. I'd just say, "It's time to clean up! Can you grab that bin, and we'll put all the toys in it?" Then I'd cheerfully guide and prompt as needed - "Nope! We can't go off and do that yet. We have to finish cleeaning this up first. Could you grab those socks over there and put them back? Thank you!" At that age it's completely normal to have to sit and prompt every single step of the way. Yes it's tedious, but that's how he'll learn to do a thorough job. I still have to prompt some(though way, way less) with a 7 yo! They're still learning to even see the messes, let alone to realize that they didn't get all of it. And we get to help them learn.
You're offering a lot of choices for things that aren't really choices (like the nursing/potty thing). If something is non-negotiable, then don't offer a choice of whether or not to do it. Instead you can offer WHEN he does it or HOW he does it (with the hat on or not, for example). Save choices for things like whether he wants to go to the bathroom before or after pjs, whether he wants milk in the red cup or the blue one, whether he wants a sandwich or noodles for lunch, and so on. Whether or not he puts his shoes on is probably not a choice. The choice can be does he want to do it, or does he want you to do it for him. Then you calmly proceed to put his coat on him if he doesn't choose, telling him that you chose for him since he didn't choose. Or let him choose which pair of shoes if there are a couple of appropriate options. But set the acceptable choices (please just two choices at this age!) out for him, and then proceed. If he doesn't choose, you do. Just be careful to be sure you're offering a real choice - meaning you can be happy with either choice!
Also, it might help if you try not to see his behavior as defiant. He's two. Part of his job at that age is to figure out what happens when he does something. Sometimes that involves figuring out what will happen if he does what you say not to. He's learning, so make sure that what he's learning is a good lesson - that it's important to fix his mistakes (i.e. clean up the laundry he dumped) and that mama will help him fix his mistakes.