Very normal for new layers to make a mess of nest boxes as they're exploring them and trying to get the materials in there to sit the way they want. A nice lip on nest boxes helps to keep bedding in while allowing them to kick stuff around, I'd aim for 3, 4" of lip.
Leave the fake eggs in - if they're used to seeing them, it can upset them to see them gone and cause them to refuse to use the boxes (because there's clearly something wrong with them).
Leave the fake eggs in - if they're used to seeing them, it can upset them to see them gone and cause them to refuse to use the boxes (because there's clearly something wrong with them).