First of all, don't feel bad. Every friend I know with kids in this age range has little or no success with time outs. They only seem to work on a fraction of the very easiest kids, and only with insane amounts of repetition, redefining consistency to the point of madness. They're more to let the parent feel like they're doing something rather than to really change the behavior, in my opinion. I'm amazed I have friends putting 5 year olds in time outs for behaviors they've been doing since they were 2, and still haven't caught on that it...hasn't...stopped...the behavior. In three years.
The tantrums, defiance and disrespect should never be allowed to continue for one minute without you stopping it. At 4, that habit has formed (thanks to time outs) she's pretty set in her ways, but with strength of will and perseverance, you can get her behaving, responding to your verbal communication, and respecting you and being much happier.
You should not feel afraid that you are interrupting your daughter by telling her to finish something, and she should NEVER be allowed to throw a tantrum or try to hit you. She should also not be allowed to insult your dress or speak meanly to people-especially you. I have a 4 year old daughter who never would have gotten 2 minutes into any of these things without consequences. She is extremely happy and well behaved because we have kept her firmly on track, and she never got in the habit of indulging negatively.
In this situation, she should have had a consequence for not responding to your direction that she was done washing the cup. She knew you were on eggshells letting her finish in her own good time-which she was pushing to the max-and this sounds like some of the books that are responsible for this style and the way kids behave today. Then she should have been told to clean up the soap, and a consequence should have been enforced if she didn't do it right away with a good attitude. This would have prevented the rest of the chain of events, but hypothetically, if she kept being moody and defiant all night, she should have kept being disciplined (firmer that time outs), but that wouldn't happen if your first scenario is effective, the rest never happens. We've never had a night like you described in our house. And we don't allow the kids to indulge tantrums in their rooms either. they're jus not allowed to do that. All this "we never punish" stuff doesn't teach kids a better way to act.
If you do not provide true and immediate consequences for these actions and set her on a good path, you are in for very big problems. You can turn this around, your daughter is an intelligent challenging girl feeling for her boundaries. Don't short change her by letting her rule the roost when it's your turn to be in charge. If you want any specifics, let me know, but this site/book is excellent.
www.backtobasicsdiscipline.com