Actually, Boot Camp 5 works with Windows 7 and 8. I'm in the middle right now of preparing the WinInstall USB using Boot Camp Assistant, and then see if everything is still good if I skip portioning the driveAh ok I see. I will try legacy boot then but might not be on upcomming days though
I was thrown off by: "MacBook Pro (Retina, Mid 2012)" on https://support.apple.com/en-us/106412