Thanks for the info, Julia! As for my question about whether all Vampires manifest for the Final Battle or just the ones on the board currently, I think that has been self-answered as well.. In my first attempt at this scenario (that didn't count due to the missing clues mistake), there were several vampire copies on the board. In this last one (and again the Ancient Ones have just awakened, so it's over...), there are none. I'm sure Avi wouldn't have intended there to be none present for the Final Battle. While it might be a cool game mechanic to have it be a variable number, it would probably be too easy to just keep the board cleansed of them.
The General Rules for these scenarios state that they are intended for people who have "all the sets from Arkham Horror to Innsmouth". Apparently that wasn't intended to include the card expansion sets... I have been using all of those, and, yes, it does make it pretty difficult. I didn't use any additional Heralds (other than Janus), just the expansion materials themselves. I did use the Organized Crime organization/institution, from the Miskatonic Horror expansion.
In truth, I was kind of happy to be rid of "the nun" when she was devoured, however.. I don't usually play with her. In this last attempt (a certain loss in Final Battle, of course), she was semi-useful at times. I started with Sister Mary, William Yorick, Gloria Goldberg and Dexter Drake. Drake was unceremoniously devoured late in the game, which was too bad because he was loaded with valuable stuff. It was because of being "twice cursed". (The first time was due to the effect of an Exhibit Item, from the revised Curse of the Dark Pharaoh card expansion.) Being cursed is just nasty. That's one of the more fearsome of Ancient One powers I've seen. In this last game, the investigators spent a disproportionate amount of time and resources getting blessed and trying not to be cursed. A couple of blessings were lost practically immediately by the curse mechanic.
This is a very interesting scenario. I usually play AH with one board expansion and one card expansion. So I guess the intention was that NO card expansions should be included...? I think I'll try this first scenario one more time. Is it the expectation in this league that each scenario should be defeated before moving on to the next? Thanks again for the info.