I did something similar when I did a purge of former menu items. For me, I was hesitant to do such a massive change to a live database.

Here's what I recommend: create a new location (Account & Settings -> Business -> Locations). Make that location match your current item library and settings. Log out of your app and back in. When you log in, it will ask what location you want. Point it at the new location.

Now you can make all the changes you want to your normal location without fear of borking something your employees need. At any time you can do the log out/log in trick to see if your changes are what you need. Once you're happy with your changes, you can put the app back to the main location. Then I recommend going back to the locations and disabling your temporary location.

Only catch I've found about this: you'll have to make sure you're looking at all locations for any comparative sales reports. If you just look at your main location your numbers will be incorrect.