Hide and exclude N/A from your data table / use local data filter / missing value codes column property to hide them.
For the labels, customize the histogram BEFORE you add X and Y Group. The settings should get copied over to all of the smaller frames when you add those groups

Other option for setting the labels which you can do from the "grid" is: set the percent label dec to one frame, right click on that frame and copy customizations, then while holding CTRL right click on some other frame and paste customizations. This should broadcast those settings to all frames you have


-Jarmo