Hi there! Sorry for the late response, I’ve been sick and then trying to catch up.
I’m also a shortie! I’ve taken a look at the Simplicity 1773 and there is a line on it marked “waistline” above this is a set of double lines. This is the point where you would increase the torso to where you need to. You can actually cut along this lines, add a piece of tissue paper in between for the length that you need and then tape it back together. I would then mark on the pattern where your full hips start, measuring down from the waistline. Measure all three pieces along this area, subtracting all the 5/8th seam allowances. Then you can compare to your own hipline measurement. It depends on how much you need to increase the pieces by. If only need to increase by a little bit, you can just alter the pattern pieces with the side seams and still divide by 4. If you’re adding quite a bit, then I would do what you suggested and add a little to all your pieces. Definitely, make a muslin first with cheap fabric and baste your pieces together so you can test the fit and make sure you don’t need to make any additional changes. Good luck! 🙂