I so want to go exploring abandoned buildings. But I've got nobody to go with :(
Reddish strips of paper you saw pasted on the walls and ceilings (like at 5:14) are called ofuda, a talisman issued by Shinto shrine. It's used to protect people from harm and disease, or used to seal in evil spirit. My guess is whoever used ofuda in this house was trying to seal in something??
The little pouch which was picked up at 7:34 is an omamori, a Shinto amulet. People carry them to ward off bad luck and attract good luck. It's like a portable ofuda.
The doll at the end appears to be an Ichimatsu doll, a creepy traditional Japanese doll that originates in Kyoto.