Props are unusual and/or symbolic items straight out of the story. They’re important because they help kids feel “inside the book,” but they’re most valuable as tangible symbols for talking points, as “ways in” to talking about themes, characterization, and key plot points. Showing is more powerful than just talking, for the same reasons we tell kids “show don’t tell” in writing.
Having said that, there’s no need to find all the props we suggest! Just one might be enough, depending on the Takeaway Topic you’re emphasizing. And you can ask your kids to be part of the “treasure hunt,” telling them to keep an eye out, as they read, for strange items in the story that they might have access to. Encourage them to think “close enough!” (Grandma’s old violin? Perfect to bring for Adam of the Road! Mom’s fancy perfume bottle? That’s Amy’s Christmas sacrifice in Little Women—and so on.)