Gist
The calves stabilise the ankle and may assist the final rise, but ordinary step-ups do not provide the repeated plantar-flexion range of dedicated calf raises.
Step-ups involve the hamstrings during hip extension and control, but they usually serve as secondary hamstring work beside hinges and curls.
Yes. The working-leg quadriceps extend the knee to raise the body onto the platform and respond well to progressive loading and controlled lowering.
Yes. Loaded step-ups can build the glutes when the platform height and torso position create meaningful hip extension and the trailing leg does not dominate the ascent.
The hamstrings assist hip control in lateral lunges, but the exercise is not as direct or measurable for hamstring growth as hinges and curls.