The function's the same as the Elizabeth, Theo, and Margaret ones; I just wasn't sure if they were any good.The Nanako and Marie DLCs just have them replace Fuuka and Rise as your monitor, I think. It's cute.
I bought the Nanako. To be honest, she's not quite as endearing here as on the show. Maybe because she's talking constantly. Her character isn't quite the same for that matter; while she's still innocent, there are times where they aim for innocent and end up making her sound stupid. I've set her to Labyrinth voice so she'll speak about stuff on the map. For the battles, I bought Elizabeth.