Oh dear lisalisa . I can't suggest much except to remember to ignore her bad' behaviour as much as possible. So when she hits her siblings, say no' firmly but calmly, and then make a fuss of the `victim' so she sees it's not getting her the attention she wants (I assume that's what she wants??). As for taking a dislike to the nanny, I'm stumped. How's the toothbrushing going? I actually often bribe my ds by saying I'll read him a story while he's brushing. Is there anything (harmless of course) you could bribe her with?
Kid, ignore as much of your ds's behaviour as you can. Also, try to avoid doing things when he's tired or hungry if possible, as tantrums tend to be much worse at these times. And don't suddenly take him away from something he's enjoying, give him some warning, for example, that's it's time to leave the playground or whatever. He'll probably understand a lot of what you're saying to him by now. But you'll probably just have to get used to being embarrassed by him in public. Don't worry too much, it happens to most of us!