Can any paper be used for decoupage?
You can use pretty much any kind of paper, that you want. You can use Magazine Paper, Newspaper, Wrapping paper, Wallpaper, Paper Napkins, playing cards, crafting paper and even fabric. As long, as the Decoupage glue, that you are using, can glue it to the surface of your project, then you can use it for Decoupage.
Does Mod Podge really take 4 weeks to cure?
Hard Coat Mod Podge dries clear with a non-tacky surface. Apply a clear acrylic sealer (either brush on or spray) to the surface after it has cured 4 weeks.