Question

When the Talmud says, “the water channel flowed backward and the tree was uprooted from its place,” that is certainly not a historical datum but an idea, or that some tanna slept for 70 years, and so on. But let’s say statements that appear in the course of a Talmudic passage, and not in aggadic material—do we necessarily have to accept them as they are? 
For example—a serious Talmudic passage like the one saying that the Jewish people began idol worship only in order to permit themselves forbidden sexual relations, and they raise objections and answers so that it seems they really mean it—are we obligated to accept that as historical truth, or here too can one say that it is coming to express an idea?
When there is a dispute between two amoraim in the Talmud, does it necessarily mean that they actually disagreed about that, or that the editors of the Talmud wanted there to be a dispute about it (according to your approach—to create a range of possibilities and dynamism in halakhic ruling), and therefore attached the names of amoraim to it, even though they did not really disagree about it? And can one say that there are amoraim who are entirely fictional and never existed at all?
I am not asking whether this is specifically on the conceptual side, only whether it is logical and reasonable to say that it is conceptual, or whether in your view that is unreasonable.
Thank you very much, and blessings to you in this world and the next!