What we know is that the game is going to be released by chapter or 2 at a time and characters are going to have their own chapters/levels. So we can also guess based on 4 confirmed women and 2 men, there will be at the least 6 levels. None of us know how big the focus is going to be on story elements, so they could only do 1 chapter per character... but there's likely to be multiple per character. They have the potential to keep adding levels for each/any character even beyond whatever story they have planned so far.
Because none of us know how many chapters they have planned to do, and they aren't going to answer that question directly, we can only wait and see how they handle doing it. We don't even know how they're going to tackle a gallery (although confirmed in the past), or whether they'll give us any number of 'sandbox' maps where we can choose who to play, but that can also always be requested if we don't get it. But again, we don't know, and they're not going to spill the actual details about stuff like that other than 'yes' or 'no'.
So we wait.