Unless the dancers are all permanently in a line doing the can-can, there are likely always going to be occasions when masking occurs. I don't see this as being avoidable on a single camera shoot, one take.
Your 24mm is going to have a good depth of field, but within that, because you're relatively close to the stage, you will see quite heavy 'sizing' differences between people at the front to those at the back - relative distances being large from that viewpoint. This can also affect your apparent stage size, making the far ends seem surprisingly far from the near point.
A 70mm is going to look pretty 'cinematic' compared to that, but you might have to compensate with a really tight aperture [& high ISO… potentially noisy] to get enough depth of field for the whole stage, which will reduce the 'cinematic' feel at the same time. You will also get what people inaccurately call 'distance compression'*, when the sizing of people at the front & back of the stage will be closer to parity, because the relative distances between them compared to your camera position are smaller. This can lose your sense of depth.
A 50mm might just split the difference enough to retain a sense of each; DoF without the 'compression'.
One thing we don't know is your sensor size. The larger your sensor, the larger your field of view for any given lens length. This could make all the difference between choosing to go with the 50, or even a 35mm. Full-frame, even the 70mm might work, though for a one-off performance, I'd play safe & use something perceived as more 'what the eye sees', 35 or 50.
*This is a matter of perspective & angle of view. What is perceived as 'compression' is really a misunderstanding of the effect as seen through the lens. It still looks like compression, so that's what people call it, right ot wrong ;)
