I now use the MOZ_PLUGIN_PATH variable in the run-mozilla.sh file for the firefox browsers instead of relying on symlinking. That way the getflash script is not having to be constantly updated with any changes to extensions.
The getflash script also creates a /usr/lib/mozilla directory if not existing, and symlinks /usr/lib/mozilla/plugins (if not existing) to /usr/local/lib/mozilla/plugins (now our standard mozilla plugin directory and where libflashplayer.so is linked to). Since chromium recognizes and uses /usr/lib/mozilla/plugins, the getflash and resulting flash.tcz should work whether installed before or after chromium. But you may have to run the getflash script again to fetch the latest copy, though it has not changed in a while.
But if you have already created and populated a /usr/lib/mozilla/plugins directory, that will prevent the linking of it to /usr/local/lib/mozilla/plugins, but in that case it is assumed you know what you are doing.