I've been using options 1 and 3 myself and they have both worked fine. You can find this advice by searching the web for: Techwalls "How to Get Free Google Apps Standard Account for Single User"
If you don't have a Google Apps account you can still create one for free even though it's been officially discontinued for some years not. You can use a Google apps account and simply limit the services available for the username in question.You'll still login with the but you just won't have the Gmail email service active anymore after that. In essence this will make your Google Account become the same as one created in the prior step. You can also delete the Gmail address.(I use for which I have a catch-all email set up so that I can just invent emails on-the-fly and will get emails pushed to that should anyone ever email to those, but that's another thing). it doesn't give access to that email address in any way. Note that You need to provide some non-Gmail email address to do this but it can be anything and it's only used as a username, ie. Create a regular Google account without Gmail.I have had similar cases at hand both in work and private use and would advice the following three options: Now, as Android itself doesn't differentiate between Google accounts the question in your use case boils down to: How can I create a Google Account that does not have Gmail (and various other Google services with possible private information on them) associated to the account in question?
As pointed out by Hiemanshu you need to do this by using a separate account.