It’s unusual for Karin to have an actor in mind to play one of her characters. An exception is Marissa’s mother in Finders Keepers. The “step up on the table in the country club dining room to make an announcement” personality – it’s so Meryl Streep. If she were unavailable then Helen Mirren would do it justice as well.
The stories all take place in the same building on the same Halloween night, so I do get the full length of a book to explore setting, era and place. Some of the characters are glimpsed in earlier stories before starring in their own.