It's been several years since my incidents. I believe there are similar stories out there that just haven't been told. My sister and I have experienced, what I believe to be the paranormal, a total of six separate times all within a year of each other. I was always skeptical of the paranormal even to this day, though I will swear behind my stories until the day I die, as will my sister.
She was the first to experience, what I at the time had no intention of believing, to have woken to my father standing at my dresser, (my older brother, sister, and I shared a room) he picked up a small object and she called to him, "dad". It then dropped the object turned towards her, as to been startled by her voice, slipped out the door and disappeared as it passed through the door frame. She then hurried to my parent's room where my mother was sleeping. She woke her up and asked where our father was. She replied that he had left for work hours earlier.
The second time she awoke to a little girl sitting at the end of the bed staring at her. Too frightened to move she remained in bed until morning. A little girl's story only goes so far with parents reluctant to believe their house has ghosts. A month or so goes by and this time she awakes to a woman standing in the middle of our room, again staring at her. "curiously." she says. Again she remained in bed.
Many days later I wake up to see, what I thought to be my father, standing a couple steps into our room. "Dad." I said and quickly without any noise he leaves the room where I sit up in bed and continue to call out to him. He never returns and I don't believe he was even in the house as it wasn't unusual for him to work throughout the night. That in no way prepared me for what was to come next.
I awoke one night to see my sister sitting on my older brother's bed, which was right next to hers separated by a few feet and a keyboard of hers, just staring at her own bed. I called to her quietly and continued to get out of bed and sit next to her, for this was something extremely out of the ordinary. But when I sat down I saw that she was sound asleep in bed. I turned and what I thought was my sister was now on the ground against both the wall and bed sitting in my direction. I remember going back to my bed confused and terrified of what had just happened.
The next night again my sister awoke to a little girl sitting on the chair next to the keyboard, only a few feet away. The day after that my mother moved the keyboard out of our room and we never had anything like this happened again at that house. Except one early morning during the summer.
My mother was resting on the couch when the TV turned on. Confused and in no mood to watch television she rose to turn it off. As the TV went off so did the fan she had pointed to her spot on the couch. She walked over to the fan and turned it back on and back on came the TV. Again she turned off the TV. Spooked by the unusual events checked on her still sleeping children and went back to sleep.
My sister believes that what we saw had nothing to do with them looking like anyone in our family. She is adamant that the "ghosts" she saw were wearing old fashion clothes (little girl and woman) though unsure of the man. While I on the other hand at first glance believed both times that these ghosts were family members.
I have heard many EVP's taken during investigations that were spirits mimicking the investigators. I also had one personal but brief experience (read The Inn) with a visual encounter similar to yours. I do know someone who was capable of astral projection as a child, but she was aware that it occurred. Since you and your sister have discussed your experiences extensively and she has not made you aware that she has this ability, I doubt that is the case. It appears that the spirit (s) are not looking to harm you or your family. They may take a form familiar to you and your sister to try to keep from alarming you when they have manifested, or they could somehow think they are fooling you and concealing their existence by immitating someone familiar with you. Unnerving as these encounters obviously have been, since nothing bad has happened when this trickster has taken form, it is unlikely that it is anything more than curious. I would definitely try making contact and setting some ground rules with the threat that you will make it go away if it does not abide. You can take back your room/house. Where is the keyboard now?