Yes but your 日本一封信 case, likely they know who sent the letter, and some mix up happened at post office...etc. But here is different. He said he has no friends in Melbourne, which is where the parcel is from. Unless a distant relative moved there and he forgot. No return address is understandable, as is lazy to write. But the same doll again 2 yrs later?? This is strange and does sound like he sent to himself from the future???? as another jm said... Ah very confused...
I did read a case on internet where the poster shared his experience. He remembers when he was young (around 3 yrs old), he saw a "ghost like man" aparision appear in his room, looking at himself sadly. But he "knows" that the "grown up man" is himself. Then yrs later when he became a man, one day he saw a "baby aparision" appear in his room. Here he remembers his experience when he was 3 and he was sad at the time. The case was very interesting and I believe this post here.