AOM: De-Quasimodo Yourself: 6 Exercises to counteract slouching. Not sure I completely agree with the safety of I've been told not to foam roll directly on your spine. Rotate a little to roll the muscles, not the vertebrae.
I like this pistol squat progression, but i would ad to the last/goal exercise holding a pound plate and doing a front raise with it while performing the pistol squat. This not only adds resistance to the squat movement but it REALLY blasts the core!