I don't think so. I think the more correct way to frame it would be that they are charging for access to the space in a user's feed. Like renting billboard space, except the user data makes it very easy to understand where you should put that billboard.
No, Facebook sells attention of relevant users, which is a product which Facebook uses user data as a tool to craft. That's not the same as selling user data, in the same way that, say, investment houses aren't selling Microsoft Excel.
Yes, but that's just enough obfuscation for them to deny any claim they do charge. But from the free content I was able to see on this WSJ article (not a subscriber) they considered charging businesses in addition to users. Perhaps in the same way they charge for access to user data in France. Where some Facebook users can only see, for example, the first friend photo. The rest of the friend photos then appear behind a paywall. I saw this just last week actually in Indonesia from a tourist trying to show me some photos of his girlfriend back home—only he couldn't because the mobile app his the images of his friends behind a content upgrade.