As @ParticleD suggests in this post putting female headers onto a mesh device (and stacking a feather on top) blocks access to the status LED and mode/reset buttons not to mention possibly blocking the mesh signal. It’s recommended to use a featherwing doubler or trippler.
I still might try to stack something on top as I can see a few ways to mitigate those concerns… the mode and reset buttons are tied to pins which could be propagated to a stacked featherwing… the status LED could be visible if you put a PCB hole in the top featherwing or perhaps use a light-pipe of some sort… the mesh signal could go through an external antenna (when they enable that functionality). If you try, let us know how you make out.