A wiki of a sort may be something to consider for sure! There are 19 dolls in the normal mode, it is true that it isn't mentioned and it could be, but the estimated time for one one ending is an hour. When it comes to ending, the 4th ending (if it is the one you mentioned) is the last one, yet it will leave you with a lot of questions, but that is expect. As this story is not at it's end just yet, we will see eachother again soon! More answers await in the upcoming endless mode and in new titles altogether!