you appear in the newspaper?
Or ... are mentioned ...
Tried that, rejected. Thinking it should be accepted
So is "Ihr seid in der Zeitung" wrong or weird or perfectly normal aswell?
it is (a bit) colloquial. Because physically you are not in the newspaper. It is only a picture of your face which is presented in the newspaper or a little sentence which mentions your name.
Is "Ihr seid in der Zeitung" correct for the same meaning?
You are standing on the newspaper?
That would be: "Ihr steht auf der Zeitung"
Why is this not "Sie stehen in der Zeitung." or "Du stehst in der Zeitung."?
Why are we using the dative form of the personal pronoun?
"Ihr" is an informal 2nd person plural pronoun.
It appears that this means to be listed in. This is from a dictionary:
in etwas [Dat.] stehen = to be listed in something
[e.g. a phone number in a directory] = [z. B. eine Telefonnummer in einem Verzeichnis]
Why not "She is in the newspaper"?