5-yo girl, constipation, encopresis, bedwetting

My daughter very much dislikes going to the bathroom. She's much too busy to be bothered with it. I see that she needs to go, and tell her to go, and she sometimes denies it or says, "But I already *went* potty today!" as if she should only ever need to go once. She holds urine and stool until the urge is irresistible, and then runs to the bathroom, and dances in front of the toilet, trying to hold it longer, claiming that she is afraid she won't make it in time, even though she is standing right in front of the toilet.

She often cries that she doesn't want to make a bowel movement, because it will hurt. She recently started soiling herself without realizing it. I smell it, and then help her clean up. She also wets the bed if we don't take her to the bathroom in the middle of the night. Usually if we take her after about two hours of sleep, she can stay dry the rest of the night, but if we wait much longer than two hours, she has already wet the bed by then.

She's average height, thin, pale, almost translucent, and sensitive skin, very curly brown hair and pale blue eyes. Bedwetting episodes, if not discovered immediately and left until morning, produce a rash. Frequently wets herself and doesn't realize or tries to hide it, resulting in a yeast rash. Picky eater. She tires easily in the heat. Extremely sociable, bright, seeking the attention of strangers, offering up personal details without hesitation. Quick to anger, physically attacks siblings over minor disputes. Also kicks and hits parents over disagreements. Frequently perceives injustice where there is none. Whines frequently.

Thanks in advance for any advice on how I can help her. We are currently trying to increase her fruits and vegetables to make it easier for her to go, but her pickiness makes it a challenge.