This summer we plan to drive through the following countries: Germany, France, Spain and Portugal. The group consists of a German citizen and two non-EU citizens having a German Schengen C visa. Note that Germany doesn't give tourist visas currently - this visa is issued as an exception (significant family event).
Currently these countries seem to only allow traffic from other Schengen countries. It's not clear for me what is meant by that: the last visited country, the countries visited within last 14 days, or the country of citizenship. Note that the two non-EU citizens are not residents of the EU: they are on a short-stay visa. I think it's an unusual situation, because such visas are not commonly issued at the moment.