Explanation SPOILERS
For as much of a mundane retread as this film was, albeit with a decently suspenseful climax, I did like how it effectively tied this film to the original and essentially explained everything in a not very "in your face" sort of way.
So, once you spend the night the witch is able to trap you in a sort of time loop. However, this time loop varies from person to person, depending on what the witch wants to do with you, and you could have been stuck in the same night for YEARS whereas others have only been going through it for one night.
The girl we see at the beginning of the film in the footage found by Lane is Lisa. The witch presumably flung the camera into the woods, out of the time loop, for Lane to find and thus lure everyone into the woods.
The people Heather sees in the corners in the ORIGINAL film are these new characters, including her brother, from 2014. Time is not linear in this section of the woods, and everyone coexists during different timelines. This makes sense because only these 2014 characters understood the concept of facing the corner to avoid looking at the witch. Heather sees her brother there, standing in the corner.
Likewise, James does in fact see his sister wandering around the house. He sees the version of her who has been wandering around that house for over a decade, lost in time. Then, at the end when he turns around because he thinks he hears heather, he DOES in fact hear her. Heather from the 1990s is there, seeing her brother standing in the corner. Time is not linear. They are both there in that moment at the same time.
While this could be confusing for some, it was an interesting way of tying the films together as well as giving a fundamental explanation of the witch and the goings on in the woods. The only other alternative for this film was to fully explain the witch, in a very blatant way, and, what, have Lisa "fight" the witch? That's even more ridiculous than some would consider this time loop scenario to be. Not to mention cliche. Again, the film as a whole was just alright, nothing new in terms of scares or general plotting. But the time twist was a good way to go about this story.