At the edges, like the Set versus Cain thing, it can be interesting, but in part because it's not really relevant. But I find too much ambiguity to be very frustrating; if I'm running a game, I want to know the power structure of the city, including who's running things from the behind the scenes, not a dozen different viewpoints, including the local idiot who doesn't understand that the only reason his gang hasn't been messed with by the police is because they have real criminals to mess with.
I'm not sure how the OP's plan is going to work. Most stuff that's written non-canon has a canon behind it somewhere, unless, again like the Set versus Cain thing, it really doesn't matter. If you quote two sages as if they are reliable sources, and one says that a city has a small minority of humans, no more than 4,000 out of a quarter million inhabitants, and the other says that the same city has 200,000 humans living there and that they make up 95% of the population, it's not going to be interesting or fun; it's just going to be frustrating. Unless the sources basically agree, the DM is going to have to make it up from scratch. Unfortunately there is canon; you have to explain why the two sources disagree. If the sources disagree too much, then I don't see you having a useful basis for a campaign world; you have a bunch of quotes that you can use to make a campaign world.