Now, about From s5, the future season finale...
I'm not sure how many eps we will have, I guess 10, as usual, but at this point on the story there is no room for slow storylines or new characters or they won't have time to wrap everything up. ESPECIALLY considering they are fucked the moment the sun goes down and that's supposed to be in just a few hours:
They don't have the talismans and they still haven't noticed.
The dolls are still out there and they don't care about the talismans anyway.
Everybody is panicking, for a very good reason (earthquakes, sudden night, etc) and they will probably start turning against each other now.
They still have to deal with Henry (trying to kill his son), Elgin (will be missing), Kristi (grieving Marielle) and Clara (working with Sophia).
And Jade and Tabitha have the bones, yes, but they don't know what to do with them at all. I don't think people are going to be happy about that either.
The clock is ticking and the monsters are coming.
So for me, the only way to make the season finale work is rushing it forward. They can have one or two eps to set a few things, but the rest of the season better be a long multi-chaptered big finale that can give us some answers because I don't want another open-ending show on my list.