Totally Called it, I had the feeling that Murphy was shooting for a different story each season revolving around new characters. So yes I assume the Harmons will return albeit it will be now as the Ghosts of house.

I'm not giving up on this yet, I've stuck through it with 6 seasons and I want to see how this will end.

Also there is a possibility that Ben may be in a psych ward due to the fact that you can see intercut scenes throughout the birth of what appear him trying to escape?

It's getting to the point where they are all going to die and become inhabitants for the next people who enter the house. Quite ingenious actually.