The Film Crew

Kazuo

The director of the documentary and thus the leader of the film crew.

Action Dad: He's Emi's father, and will go through hell to ensure that his crew and his daughter make it out alive.
Death by Adaptation: Unlike the movie the game is based on, Kazuo can potentially die during the events of the story
Kill It with Fire: He starts off with a lighter, which comes in handy for burning ropes and maggots alike.
Lightning Bruiser: In spite of being a middle age guy, Kazuo has the highest HP in the party, the second best defense and goes before any enemy in battle (like all other party members). His lighter also deals massive damage to skulls and worms.

Asuka

A professional art restorer.

Improbable Weapon User: Subverted. She takes a vacuum cleaner to the mansion as her personal item - and cannot use it in combat. As for cleaning up glass shards and finding out how everything went to hell, though...
Mercy Kill: Ends up having to do this to Taguchi in the movie.
Spared by the Adaptation: Asuka can survive the ordeal, unlike the original story where she died. She and all her companions must survive to achieve the Golden Ending.
Utility Party Member: Asuka has the second lowest defense and is restricted to what weapon she can equip, making her a poor fighter by default, and her vacuum cleaner can't be used in battle. However her signature item is still useful to remove glass shard to open new paths and ways to traverse and cleaning up frescos for Taro to photograph and obtain a hint to solve puzzles from them.
Wrench Whack: Uses a wrench in the film to put Taguchi out of his misery.

Akiko

A nurse accompanying the film crew.

Death by Adaptation: Akiko can potentially meet her doom at any point in the game, unlike the movie where she survived.
Dressed to Heal: Her overworld sprite depicts her wearing a stereotypical doctor's hat and scrubs. Do you really need anything else to scream that she's the party's medic?
The Medic: She's the one who can cure all the common status ailments with her Medkit. She cannot use it to heal HP however.
Squishy Wizard: Her Medkit is a very useful survival tool, but Akiko herself has the worst defense among playable a characters and limited selection in weapons like Asuka. It is just not a good idea to send her in battle alone.
Support Party Member: Akiko's medkit is never used for any puzzle, making it (and herself by extension) technically speaking not required to win the game. You will still want her to be around all the time though, unless you are planning to pack some pill replacement items, as her ability to cure crippling status effects is crucial for the party's survival.

Taguchi

The documentary's cameraman.

Camera Fiend: He's the one with the camera, so if anyone is to find out from the frescoes what the hell happened, it'll be him.
Dies Differently in Adaptation: Downplayed, if he bites it, his death will be the same as in the movie, but the circumstances that lead to it will be different
Half the Man He Used to Be: Should he die in the game, this is how he goes out. It is also his fate in the film.
Light 'em Up: His camera deals effective damage against bats and ghosts.
Lightning Bruiser: Less so than Kazuo, but Taguchi/Taro has the second best HP in the game, the best defense and his camera can make shortwork of certain enemies.
Spared by the Adaptation: Can survive the events of the story, unlike in the source material. He and the rest of the film crew must all be alive at the end of the game to achieve the Golden Ending.
Unwitting Instigator of Doom: In the film, he's the one who kicks over the memorial tower. It ends up costing him and Asuka dearly.

Emi

Kazuo's teenage daughter.

Action Girl: She is not as vulnerable as the others girls in the team, having the best defense stat among them, and not being restricted in the choice of weaponry like them.
Death by Adaptation: She can perish during at any point in the game, unlike the source material, where she survived.
Master of Unlocking: Her personal item is a key. Do the math.
Tagalong Kid: While everyone else are grown-ups, Emi's a teenager. Still doesn't hinder her from being a valuable asset, however.
Utility Party Member: Emi's signature item is useless in combat, being just a key, but vital to gain access to the rest of the mansion.

Other Characters

Yamamura

The manor's old groundskeeper.

Ambiguous Situation: Was he Ichiro Mamiya himself, or was he just another random victim?
Cruel and Unusual Death: He ends up being melted alive. And then to add insult to injury in the movie, his skeleton collapses.
Haunted House Historian: Seems to know far more about the manor than what a lowly groundskeeper should know. Not that Kazuo and co. are complaining, though.

Lady Mamiya

The manor's matriarch, Ichiro's wife and the one behind the horror.

Accidental Murder: Accidently set her own son on fire when he was playing in the incinerator. The other children were deliberately murdered.
Better to Die than Be Killed: Threw herself into the same incinerator she used to burn children alive.
Final Boss: She's confronted as the final enemy of the game.