I think "Be humble" would be a better one-line version. They're basically about not believing oneself superior to others.
Not really. Notice the stuff about you not being better than us or having anything to teach us. Janteloven has the flip side that everyone thinks that they have nothing to learn.
More like "Be humble or we will exclude you from society".
Or maybe: you are not to give reasons (display of wealth or whatever) for other people to think of you as someone who would feel superior to others.
I don't know if you live/have lived in Scandinavia but this is depressingly accurate.
Not true, you can think, as long as you think like everybody else.