The Jetta? Nah, not really. Maybe a tiny bit of the rear lights, but that's it. The current Jetta's design language comes from the mid 2000s refresh. The current Jetta is toned down from that atrocity on mankind. The 2019 Jetta coming soon has some Audi influence, but it's minimal. It's a conservative approach. The A4 simply has more aggressive styling where it needs to, sharp creases, way better interior, etc. The only similarity I see is the rear lights, but even those aren't the same.
Plus, the new Jetta will only be getting a small motor initially or it's the only motor. The 1.4 turbo may be a hard sell given its performance numbers, but I think it'll sell well in congested areas where you don't need a lot of power, but also want some refinement without paying through the nose, and decent MPG.
Overall, I'd say the Passat is closer to a base, stripped out Audi, but it still has evolutionary cues from the VW lineup. I think the new Passat will garner a lot of attention alongside the Arteon which are finally coming over in the latter half of this year. They've been available in Europe for a while now. If the German marques can keep upping their reliability each year, it may offer a new marker for lower trims to compete against the Japanese.
It's dual benefit, IMO. MBZ, BMW, VAG, et al. offering cheap entry models or cheaper vehicles on the more affordable spectrum allow them to fund their other projects for their higher end vehicles. There's always going to be cries of brand dilution.
Edit: Forgot to mention, I saw a black Bentayga in the wild on Saturday. Not bad looking.