Not an expert on teh Kindle's but do use Androids, which are alike in many ways (Even read Kindle Books on the 'droid)
If they all have the same ACCOUNT (not profile but account) Apps may be installed across the board. Android aps even install to my Chromebook now Even if I don't want them (Strange grin).
However on each device I choose the apps on the "Home Screens" and I can from the aps list menu choose an item that is titled HIDE APPS.
I tap that. then tap each app I do not want to show on that device, and tap DONE.. The aps are still there (When the child ages you unhide) but they do not show up.
