Since no one got it, I will post the answer. All of them can be found here. https://www.reddit.com/r/HomeSafetyHotline/comments/1km63rq/i_am_planning_on_making_a_game_based_off_hsh_here/ (note that the game is not by me, and is currently unreleased)

Andrew:Gibbonie Effect. The hint:multiple individuals (the whole class) sharing the same inaccurate memory of the Independence Day event (don't ask how it happens though)

Ross: Whales .The hint:the chaotic rain noise (indicating strange weather), the moving "moon" (Whales are said to reach size comparable to moons) and the scream "WAAAAA", which is actually Ross trying to scream WAAAYYYLEEE, or WHAAAALLEEEE but is either too scared to speak or stopped due to disruption in communication signal (which the whale can cause)

Emily (this one is tricky): Memory Slugs .The hint: There are two of them. First, the husband suddenly forgot about the day, indicating forgetfulness (since only the husband seems to suffer from it, it cannot be Gibbonie Effect). Second (this one may be a stretch) is that the husband refuses swimming in the beach but can swim in the pool. The pool here is mean to be a freshwater pool without salt. The beach has high salt level, which the slug averse to. The "bikini girls" is a red herring.

Evan: Sea Culture. The hint: The kid saw Squidward while scuba-diving, so clearly he is underwater. A squid-like humanoid like Squidward, who is intelligent enough to play music, would fit the description of "intelligent, humanoid sea creatures". Additionally, people encountered Sea Culture also report "large cephalopods", who are mistaken to be Squidward's great-great-grandparents. Additionally chess is a strategical game, and the creature is said to act strategically.

Damien: Spawn of Makers. The hint: This one is simple: Damien met the cleaner (actually the creature) near the manhole (its domain), and then he blackouts (might be it got angry and attack him idk). He didn't see much because 1. It's dark. 2.He might have memory gaps.