What your are observing is called 'premature pubarche' and it refers to the isolated appearance of pubic hair before the age of eight years in girls. It appears to be more common in girls. Premature pubic hair development is seen in approximately 15 percent of girls under eight years of age. Obesity is a common associated factor in these girls.
So, I am assuming that this is likely a normal finding, but given the other symptoms that you are describing (taller for age, weight gain, cravings, hyperactivity / somnolence) I think that this should be brought to the attention of her Pediatrician
so that she can be further evaluated.
I can imagine that this is initially disturbing, but I believe that, in her case, it will probably just be a variant of normal - but best to be evaluated in person. Good luck!