It's supposed to work in 2014 HF1 but reverting to that will present other issues that have been corrected in SP1.
2013 may work fine for this as with 2014 backward compatibility with 2013 was intoroduced in 2014.
There are several caveats with this but for the most part as far as I know most basic features switching
back and forth is possible.
The major differences are any new features that were added to 2014 wouldn't be available in 2013.
Gradings can also be a problem if brought from 2014 to 2013.
If you wish to install 2014 SP1 Here is the readme file.
Sorry I can't answer that question as I have no knowledge of virtual machine.
Maybe someone else here has tried a similar scenario.