Nah, the A7 doesnt share any parts with VW's (aside from stuff like switch gear and clamps and shit like that). It's only the MQB platform Audis that are rebadged VW's- the Audi A3 is basically a GTI and the S3 is a Golf R, the Audi Q3 is basically a Tiguan, etc.
The A7 is derived from the A6 and is on its own architecture. They don't share any drivetrain and platform components with VW's except the Phideon which we don't get here.
Look at the proportions on this car. What VW can fit a longitudinal V8?
Here is a CC for comparison.
It really becomes apparent when they're parked next to each other that they're derived from completely different DNA, despite some superficial outward similarities.
fun fact: VW spent billions on a state of the art factory to build the truly upscale Phaeton- it was a VW that rivaled the S Class and 7 series in luxury (and in price). It bombed because no one wanted to pay Mercedes money for a VW. One of the biggest blunders in VW's recent history (until Dieselgate).
They eventually salvaged some of the investment by buying the Bentley brand and repurposing the Phaeton platform to Continental GT's. It was a massive hit.