About the 3rd way - although the hacker's approach of copying the files may work sometimes, it wouldn't in this case (or more precisely it will be prohibitively difficult) because the Hyper-V and vSphere file formats are different.
However Converter can do that (for Hyper-V 2008, it can't for 2012, regardless of 'R2'). You should power off the VM and select 'Hyper-V server' in source type. Perhaps this could be even faster (though I don't know actually).
Regards