I've StreetPassed with a few other Fire Emblem Awakenings players, I can shop or battle their parties on my map. I need to earn more money to buy some high level items for sale by one StreetPass party. How long will the StreetPass parties stay on my map?
A sortie party met via StreetPass will stay on the map indefinitely until you Parley with them and either Fight or Shop. However, they will be defeated and leave if a Risen battle appears on their spot and you don't immediately help them out with that Risen battle.