Hello Ryan,
I am not sure about the “you do not have permissions to edit this page” situation, I wasnt getting that error but then again I do not use Pages much on my web site other than to test the new Power add-on. 4.5.06 RC tested out that the Store Pages icon on the Admin Sidebar does reappear. If you have another question or the update created a new issue could you please let us know or start a new thread. Appreciate it.
CiCi.