Others have asked how long until the game ends. I'll ask a question that may have an answer the Arcadean is closer to knowing.
How long until Act 2 ends? As i progress, im seeing the available empty hearts for the girls, the available empty slots for training, and the available property options filling up. It's unclear if there are things that will be added or opened before Act 2 ends, or if what's achievable now defines the limits for Act 2. I wouldn't be surprised if Act 2 is complete before this summer ends.
Related question: will there be a delay between the last Act 2 update, and the first Act 3 update? One can imagine a desire to perhaps frontload things a bit, to really get into the act. There may be new locations, new or altered character designs, etc. If the transition is anything like going from Act 1 to Act 2, there will be a certain amount of exposition necessary to prep us for the new situation. The normal (at this time, at least) weekly update cycle is very nice - but could become impractical during the transitional phase, at least. Any predictions, especially if Act 2 is as close to completion as it feels?