Questions I need answering!

Following the series finale, obviously I am left with just as many questions as we got answers. Whilst I have a pretty basic theory of what has happened in the past, there are still a few large questions and plot points I have no idea about and was wondering what people think.

Who is the boy in white? He has to be important somehow right? Could it be Thomas given that all of ‘Tabitha’s’ other kids seem to have some sort of special connection to the place.

Who is Martin? I have absolutely no theories or idea about this one yet.

What dragged Boyd and Sara around in their tent? And will we see these monsters?

So the playing of the song seemed to cause Jade and Tabitha to remember the past, do you think it has any other impacts? Obviously it must be pretty important to cause the yellow man to come out.

Who is the Kimono lady?

Thanks all! Keen to hear what you have to say :)