I'm doing the above migration (we have 6.5) and I have moved the /etc/clientlibs to the ui.apps as required.
I have a bunch of other custom stuff in a directory called /etc/<our site>
These are some "Pages" that contain configuration used by some of our components i.e. not ordinary pages for Editors to use. Also some files used by the robots/sitemap etc
My question is :
Is it o.k. to leave them in /etc/ ? I know that Adobe seems to be encouraging people to stop making /etc a catch-all place for random stuff.
I don't want to move them to /content because they mess up the sites page.
I would not move stuff to /apps, because that's normally read-only and not writeable (except for administrator group by default); in AEM as a Cloud Service it's not writable at all during runtime.
If your configuration is supposed to be changed during runtime I would store it either in /content or /conf.