I would assume that it's OK to install on a Windows VM in a MAC. But make sure the Windows 7 is fully updated to SP1 and all subsequent updates. This may help: Windows 7 Service Pack 1 (SP1) - Installation Tips
Also make sure, even if you never use it, that Internet Explorer is version 11, as McAfee uses it in its interface.
Simply uninstall McAfee in the normal manner from your old machine via Control Panel > Programs.
Then go to your account page whilst in the VM and download the software once again. Antivirus Software and Internet Security For Your PC or Mac | McAfee