It seems to me that Boot Camp seems to sometimes work, sometimes not, on certain systems. To be honest right now I'd either only run a VM if possible (not in your case), or do a native install of Windows 8.1 without Boot Camp (EFI boot), only using Boot Camp Assistant to grab the required drivers. Wouldn't bother with Windows 7 at all.
Sure, the EFI boot is a tiny bit more hassle to do, but probably worth it.