Problems with "Your info" in Win10 after Office 365 install

I set up a small LAN for the customer with three Win10 Pro PCs, NOT a domain setup.  Had I known to look, I suspect all would have shown "Local Account" on the Settings > Account> Your Info page, with the picture of their choice.  But the problem is that now they all show (fake name) "bob.jones@abc.compress.com" with Bob's profile picture.  If either of the two who are not Bob change the profile picture, it changes it for Bob as well, getting him upset, and I've heard that other things are unexpectedly changing as well for all three of them if one person makes a change--but I don't know any details yet.

I suspect that this all started when I downloaded Bob's Office 365 subscription for all three PCs.  On the Microsoft site it showed that it could be installed on up to five devices.  But now I'm wondering if that only meant Bob's devices, and that the other two PCs need to buy their own subscription in order to be "separated" from Bob.  Is that true?  I need to know for sure because they are going to be quite upset if I tell them each have to buy their own subscription.

Back to the Settings > Home> Your Info screen....it has place where I can click on "Stop signing in to all Microsoft apps automatically".  Would that solve all these problems?  Would the Office 365 subscription they are sharing still function properly?  

Note that their individual Office 365 installs ARE working properly...Outlook is set up for each individual email address and getting that person's email, and Word is getting the correct local documents for each user.

Please help me understand how to handle this, so each computer is independent of each other--just as they were before I installed Office 365.  TIA