The government of Saxony owns a substantial stake in Volkswagen AG and would never allow them to be purchased by a foreign entity.
[1] https://www.volkswagenag.com/de/InvestorRelations/shares/sha...
What they would do with the bean counters, I can not predict. Tesla hates beancounters, but you need them. The software part of VW, which is now their most important asset, could be of some value, but I doubt that that it would be of value to Tesla. VW is now mostly a SW company, and far behind Tesla.
Audi would make technical sense, because they have the most advanced engineers and have the best assembly lines. They are also much better than Tesla in every aspect. Esp. SW, powertrain and battery tech.