? is a ligature and the other two, I believe, contain diacritical marks...but I'm not familiar with their uses in Norwegian or other Northern European languages.
You may as well have posted a character containing an Umlaut.
Then a later edit...
So I did my homework and discovered that the characters ? ?, ? ?, & ??
...do have the distinction of being considered full letters in Norwegian & Danish. Icelandic has the ? ?.
However, to be fair, one might translate the phrase "Watch "Jeopardy!", Alex Trebek's fun TV quiz game" into any of the above languages and demonstrate how it likely does not contain every letter of the alphabet in that language...
This phrase
does in Norwegian:
H?vdingens kj?re squaw f?r litt pizza i Mexico by.

This phrase
does in Danish:
Quizdeltagerne spiste jordb?r med fl?de, mens cirkusklovnen Walther spillede p? xylofon.

And how could we dismiss Icelandic?
K?mi ny ?xi hér, ykist tjófum nú b?ei víl og ádrepa.
