HI Towcybers, in your step #1 do not turn off iCloud in your iOS device, instead just turn off iCloud drive inside your iCloud preferences, you will still be signed in to your iCloud account, you just turn off iCloud Drive, just that service. In my experiment this action deleted All Local copies in my iPad. Now, at this point do these tow steps in any order : Turn on the iCloud Drive switch back on ( remember, I am not talking about iCloud as a whole, just the iCloud Drive switch inside iCloud config) and restart your iOS device. Once you have turned on the iCloud Drive switch and restarted (in any order), go ahead and open your iCloud adrive app and you will probably see just a couple of folder, just wait and be patient. Assuming your iOS device is connected to the Internet, more and more of your folders in your iCloud account, (including your Mac's Destop and Documents folders if you enabled this new functionality in your Mac running Sierra) will appear in your iCloud app. It will take a couple of minutes before you can see all of them and their subfolders and all the files they contain. This is because, in my experience, neither the files in my iCloud account nor in the Mac which I originated them from were deleted or missing, at all. At this point, it is like the first time you enabled iCloed Drive on your iOS device, ie. no local copies of anything in your iOS device and ALL of your files and folders safe and sound in both, your originating Mac and your iCloud account. You could disconnect your Mac from the internet and all of your files and folders will be locally available in it. They also will be present in the iCloud servers. So, yes, if you want a local copy of any of your files back again in your iOS device, you will need to download again, but at least you will have recovered a lot of the space in you iOS device that has been taken by files you do not need any longer as local copies on your iOS device.
As a side note, this procedure also removes the iOS devices' local copies of Keynote, Numbers and Pages files. I mention this because iOS seems to deal a little differently with those kinds of files than with the vidoes and pdfs which are access from inside the iCloud app. But again, no worries, those original Keynote, Numbers and Pages files will not be deleted from your originating Mac or from the iCloud servers. Now in the case of Keynote, Numbers and Pages you can configure them on your iOS device so they download all the files in their corresponding iCloud folder automatically, as opposed to in a case by case fashion, which could be ir could not be of convinience to you, but I wanted to let you know in case you don't know about it and you find it usefull. To acces this option, go to Settings > Keynote, Numbers, Pages > On-demand Downloads. If you turn that off, all of your removed files will be downloaded automatically, but just for those three applications.
Now, if you are in doubt that by following this "iOS local copies removal procedure" you may end up loosing your files on your originating Mac and/or iCloud account, which in my case did not happen at all, may I suggest you backup all your iCloud files to an external hard drive beforehands, so in case something goes wrong it will be just a matter of restoring whatever lost.
Well, very long answer, sorry about that, I hope this helps you and other somehow, because honestly, Apple's documentation for this situation (and others) is almost nonexistent, at least in my experience.
Best regards.
