Shar hasn't been mentioned yet, but there is a prelude comic-book series begun. Dungeons and Dragons: Mindbreaker, featuring Minsc and his band encountering strange cult activities in Baulder's Gate. So perhaps we'll be bought up to speed there.
No.
I hated when this defense was brought up with the Star Wars sequel trilogy and I hate it now. You should not have to consume supplementary material (if this even meets the criteria, by the way) to be informed/educated about a key development in another product.
