Thanks for the replies! I've been distracted by the holidays and haven't had the chance to check back for a bit.
Thank you, I will check it out.
Thanks for sharing your thoughts. I'll repeat that I know I'm being kinda picky with my questions, and more likely than not the players will not notice the potential weak points, or if they do, they'll make up their own explanations, which it sounds like happened at your table. That is great!
For my part, I have little concern that just running the scenario as written will run into major problems. But, I've been reading some advice recently about how to structure and run mystery scenarios, and I'm thinking about reworking some things to put that advice into practice, as an exercise. If I manage to get that done before we play, I'll share the results here.
Short of doing that, I have thought up a few answers to my own questions that don't require much in the way of rewrites, which I'll share now. (Definitely won't force these things unless they come up, and if the players have their own ideas that won't throw things completely off the rails, then of course I'll go with those instead!)