I would not ignore as such but lesser "punishments" for teasing and not eating at the dinner table.
Be harsh. Take away privileges and don't feel bad about it. If she misbehaves, ban cartoons for a week, if she still misbehaves remove the consoles too. Don't send her to her room either that's where all her toys are. Send her to a naughty chair or yours and don't let her get off that bed or chair until she's calmed down if she throws a hissy fit for being sent there. Don't do it for a politically correct minute for every year of her life - it don't work, send her there for as long as it takes to stop the misbehaving.
If she refuses to eat dinner let her still sit with the family anyway, if she wont eat or does distracting things, ignore it, if she still can participate send her to the naughty place. If she isn't hungry for dinner she wont be hungry for anything else and keep stating that, reheat her food when she gets hungry later or simply go without for the evening, she wont starve. We don't do treats or other cooking later to cater for fussies in this house. Perhaps even involve her in cooking a meal for the family and comment on how lovely it, she will be more likely to eat it, buy her a little chefs hat and apron to get involved a couple of nights a week, it will make her feel "older" and "special".
Try to encourage her to be as independant as possible in her hygiene and toilet use. Praise her when she does things herself and off her own back. Perhaps buy her a childs hand wash and childs loo wipes with her favourite characters on. Make her feel like a big girl when she does it.
If she asks for something rudely simply refuse her request until she says "please" and make that clear too, no "please" no drinks. Enforce manners and teach her that manners earn things.
I know it might sound like harsh parenting and not everyones cup of tea but it bloody works. So for the judgemental my 5 year old has been able to sit in a posh restuarant with adults since the age of 3.5, join in conversations and be quiet and colour, etc without creating a fuss. He is very polite and eats whatever he is given, seafood, foreign street food, mushrooms, greenery and even asked for seconds on a vindaloo (describes it as "a little bit spicy" and his favourite food is "camembert") but I did all the above and believe me he has been a brat but very very rarely do we have any trouble. My DP (his step dad) is alot older than me so has a more older fashioned outlook on bringing up children so I've learnt from him, the same era as my own mum and dad and let me tell you it works better than the tree hugging rubbish in parenting books of today.