I vaguely remember hearing something about a sidestory where Silvara and the elf noble who's fallen for her* go off on their own adventure and discover the egg situation, which leads into her telling the real party about it in the main modules so they can go on a better prepared rescue mission...
The simplest answer to that last one is that Paladine is testing Silvara and the PCs - they're supposed to shout him down, then get worked up enough to find evidence that the Deal was never being held in the first place.
Well, the Leedara in SotDQ is implicitly not a banshee - even if we say that her statblock doesn't list a Wail attack because there's no circumstance within the module were she would use it she displays other powers that banshees aren't known for.
I haven't run it, but I have a few tweaks in mind for if I do.
The simplest change to the ending is that
The other tweak is half a minor adjustment, half making the implicit explicit. (Major spoilers, still)
My usual approach is that the gods are Progenitors... who, after having burned up a lot of their energy in the process of Creating, require belief to sustain themselves - and thus become subject to being influenced by that belief.
And if their latest world is successful, they're probably going...