Would shoulderstand (supported properly) be a safe and/or helpful pose for someone with slipped disc? (L2-3, L4-5)
How about headstand?
Not a good idea for either pose. Bridge and dog are the only inverted poses I would recommend. Mostly this condition needs to strengthen the buttocks working as hip extensors and as hip rotators, with mild stretches of the hip flexors – psoas and rectus femoris.
namaste Mukunda