Hi master Lee is it good fengshui if the beds are placed below the mezzanine.

More to do with stigma attached to it. 

And a dash of common sense. Here, make sure that nothing is above the bed. Else if things fall from it; is dangerous

For privacy, all personal reference are left out:-

In the context of symbolism within Feng Shui, these two headboard designs are regarded as suboptimal.

Here, a division occurs precisely at the center ...

Triangles frequently exhibit a sense of discomfort regarding their points.