I recently heard some scholars attempt to date Jonah as a later (and hence fictional) work. Is it correct to assume that traditional Judaism considers Jonah to be a historical and accurate account of the real prophet described in the book of 2 Kings 14:25?
Mikra (the TaNaCh), as opposed to Aggadaic Medrashim and Talmudic passages, are not allegories. Even when the verse is hinting a lesson, we learn that אין מקרא יוצא מידי פשוטו, the verse does not abandon its simple meaning.
There are a few exceptions, though. Firstly, there is such a thing as exaggerations when that is a manner of speaking. A famous example of this is the cities that reach the sky. This is an obvious figure of speech being employed. It 's not like something we'd read at face value, only to find out it never happened.
Another possible exception is the book of Iyov. There is one opinion in the Gemara that Iyov never existed. However, this opinion was rejected because his name and location are given, which makes it read not like an allegory. So here too, we see that we won't interpret an innocent verse as a lesson without a literal truth.
In fact, the reason we interpret Talmudic passages as allegories is because they are also a figure of speech. It is not TaNach so it is less careful and it employs figurative speech, exaggerations and allegorical stories. These become obvious once you tune in.
The prophet Yona is counted as one of the 48 prophets.