Or possibly a better idea. I think you are as OCD as I am, lol.
I mean not wanting one Windows 10 and the rest Win 7.
Rather than make the entire switch at one time and walk into the office with all sorts of small and big issues you didn't foresee (a driver here, a scanner not connecting there), why not go ahead and add that one computer with Windows 10 and see if there are any issues.
Say, one thing doesn't work (even AC). Or it doesn't have a connection for HDMI. This way you will see all the issues and anticipate them on the others.
I am not sure how much the following has changed, but one thing with Windows 10 is the auto-updates. No big deal. Except, someone reboots their computer and there happens to be a huge update. It will reboot, but install the update, and there is nothing you can do but wait. Usually only five to ten minutes, but I have had some that last thirty minutes. So, I schedule them.
Just a thought.
