VVT on a hemi does not do any EGR besides what would happen already because of poor scavenging or overlap that is already built into the cam, it will however reduce dynamic compression pressure by retarding the intake closing point so the piston can't start to build pressure until it has traveled farther up the bore and at the same time it allows the cylinder pressure to work on the piston longer before the ex valve opens and releases the pressure.

If an EGR valve helped MPG they would be on every ICE, they are just there to reduce NOX on engines they otherwise can't get low enough and nothing else.