Spooky DnD One-Shot Adventure

The characters are friends and family at the celebration. A character has made an enemy of a local spellcaster.
It is at an academy on an island which is built on the site of an ancient graveyard.
There are local nobles and merchants gathered for a masquerade ball. And a bone naga is trying to gain entry to a sacred place guarded by wards.
At some point a desperate relative of a character arrives.
As the adventure progresses there are hints leading to a great betrayal

The characters are a group of caravan guards protecting a single merchant, stopping here for the night. One or more characters is currently cursed.
It is at an abandoned palace which was the site of several murders.
There are a gang of wererats looking for buried treasure. And a hag is looking for a soul to complete a ritual.
At some point it starts or stops raining.
As the adventure progresses the characters receive a series of visions

The characters are an experienced group of adventurers looking after the place for a night. Two of the characters are friendly rivals.
It is at a cursed lighthouse which has many strange lights.
There are a group of smugglers sheltering for the night. And an old priest seeks to avoid their death, foretold to be on this night.
At some point a desperate friend of a character arrives.
As the adventure progresses the characters receive a series of visions

The characters are a group of inventors gathered for a special challenge. A character is celebrating a birthday.
It is at a grove of trees sacred to a local religion which has strong ties to the Nine Hells.
There are local nobles and merchants gathered for a masquerade ball. And a scout seeks to stop a portal opening at midnight.
At some point a fire starts.
As the adventure progresses it gets colder and there is a snow storm

The characters are friends and family at the celebration. A character is or is undead.
It is at a library of forbidden knowledge which is haunted by minor spirits.
There are hooded slaad cultists initiating new members. And a bone naga is trying to gain entry to a sacred place guarded by wards.
At some point an npc betrays the characters.
As the adventure progresses there is a series of murders