I love finding items in houses left by owners. The first house I purchased had a bunch of seed packets, and I thought of it as a Home Welcoming gift. Same when I upgraded and had a couple trees and piggies. Initially I thought they were put there by the game, but after reading the forums learn that people left them. Recently I purchased a new house in Salatu and needed to plant my own trees and get my own piggy. I hope you get your items back but it might be disappointing to the homeowner, especially if he or she is a new player.
I figured this would be a long shot, plus I really don't mind if they decide to keep them... it just means more glitch play time trying to collect them all again! (I had about 9 Musicblocks stored there :P )