1/2. It's definitely a good set up for the story! Though to be fair when the professor was cutting off, I expected it to be a case of bad internet, not a case of falling asleep lol. Not sure how to fix that, or if it would be better to just jump straight into the weird zoom part of it instead of prolonging the intro, depends really on what you're planning to do but sadly I can't tell you much since I'm not sure what you're planning to do ; v ;
3. The sounds and music definitely add to the story, I feel like they fit well, especially that drawn out creepy sound towards the end.
4. I'd love it if the art actually had a little more contrast to it, something to make it feel less like a doodle and more polished if that makes sense. Just have there be Really Dark Shadows to emphasize some of the creepiness more?
5. Not sure at the moment I'm afraid, there isn't much for me to think of other than something might go bad with the mom phone call or the subsequent zoom calls, but thats mostly just because I know what the general premise of the game is about. Otherwise, if you were to give this to me without any context, I probably wouldn't be able to figure out much :(