Really late to the party on this game. I just finished it and had to read if anyone else experienced what I had.
I knew beforehand that there was nothing supernatural going on after reading a review, plus as mentioned above you do find an invoice detailing electrical problems.
That said, I most definitely heard other footsteps occur on a few occasions. I too heard the whisper "Hey you" in the basement. It was definitely a girl's voice (Sam?). Lastly, a room I had yet to enter had the lights off, checked another room, came back to it a moment later to discover the light turned on.
I'm convinced these were deliberately placed to plant the idea that you may not be alone in the house.