Your Emmy sounds like a very typical sheltie kid at that age. An extra special treat for coming may help...I use chunks of baked chicken or a piece of fat free cheese (the kind that comes in individually wrapped slices). If these special treats are used
only for coming and she never gets these treats at any other time...it usually works. Initially give a special treat every time she comes...then gradually go to more random treating. For the loud barking at you when she wants something, the thing that I have found most effective is to say nothing and simply turn my back to the doggie who is demanding attention. Shelties hate being ignored and typically will catch on really fast that "yelling" at you gets the reverse result from what they want. Emmy, is just testing her "wings" and seeing where she fits into the pack order (your family)...and gradually she will get the message that she is not the "big cheese". Barking at cars is a biggie...I have had a couple of fosters who were a terror at this and it took time and patience to work through. What I found usually works is to select a safe place near a street that has moderate traffic. Have a pocket full of good treats (you can always sub this for a meal so weight gain is not an issue) and every time you see a car approaching, get your dog's attention and give continuous treats as the car passes by you...then praise BIG TIME for no barking. Most shelties are so food oriented that given a choice between eating or barking they will choose eating! LOL Obviously you can't employ this tactic while driving but if you can get Emmy to not bark at cars when she is sitting by you near a road, she will probably transfer the no barking to seeing cars out the car window.
Hope these suggestions help.
Trini and my gang.