No on-screen characters are confirmed LGBT+, but it can at least be inferred that an LGBT+ person may have died considering the game is about people who have passed away.
Some of the NPCs are parents who have passed away. One child NPC mentions passing due to a hereditary illness and hoping to reunite with his mother in the afterlife.
At least two cats pass away off-screen, and you meet them as ghosts. Depending on which ending you get, there will also be a lengthy discussion about a stray cat who died in a car accident, and she asks the player character to save her kittens.
Some NPCs are children who've passed away; one of the most prominent is an infant, but there's also a child who passed due to a hereditary illness, a lost kitten, etc.