I think I will explain my reasoning in more depth, for no particular reason. I chose just the final, as to my understanding, this will be basically a large scenario. Past experience with playing scenarios (or any type of gameplay where a crash could lose a lot of progress) has found that it is incredibly frustrating to play a large period of time, only for a part near the end to not function correctly (and since you generally have to play all the way to the end of the scenario to test those parts, they often end up the least tested).
In other words, I think that you should fully ensure that there are no bugs to your knowledge before releasing, essentially being a "final" (version 1.0?), but be prepared to release an update shall other users find anything you missed. Though, I don't think it would be very useful to release something that knowingly has "minor bugfixes left", simply because of the way scenarios operate.