Sounds like this girl was terribly ignored in her previous home.
No 1 issue - have you had recent blood work done on her to make sure she doesn't have a medical issue causing the increased hunger?.....Could also be the time of year, my dogs are eating more right now. BUT, I would have a thorough blood panel done.
No 2 issue - Some dogs like the attention of other people & other dogs, some dogs don't. Yours does not crave that & I personally don't see anything wrong with that. She is 100% devoted to you and that is NOT abnormal for a previously neglected puppy.
No 3 issue - I'm not sure how to answer this question because I too had one of those dogs who had been horribly neglected/abandoned by his first owner & truthfully left to die; we found him at 9mnths old, his entire life we dealt with separation anxiety issues. He also had seizures when he would stress out, so we learned to live with it, we didn't care to force issues more then we needed too. BUT....when we would leave the house & had to crate him, we would give him a kong full of peanut butter, that would keep his attention enough to tire him out, generally we'd come home finding him sound asleep.
This girl found you as her savior, you saved her from a previously horrible life, IMHO from the sounds of it; she's happier, yet fearful that the same thing will occur one day. Some dogs grow out of it, some don't.
I've had both...one that never grew out of it; yet our bond was so tight, so it did give him confidence, just could never get past that fear of being neglected again.
Our current pup, who's 2yrs old now, was also horribly neglected & abused in her short 4mnths before we adopted her. She grew out of most of it; but is superbly attached to one dog in particular, her non-biological brother; she's still skittish somewhat....does not like to just go up to people & does not like them to approach her. She won't bite or growl, but she will cower down and pee .....I won't let people approach her, I tell them to just do their normal thing, she'll come to them if she wants too, she generally does on her OWN time.