I think a lot of us assumed that scene was intended as the origin story for the Night King, even without getting outside information.
Ah, ok. It never even crossed my mind 
I assumed it was just an example of the creation of White Walkers.
I think we’ve seen White Walkers being created, such as in an early scene with one of Craster’s babies. The Night King did some magic over the baby and his eyes turned blue. So we can conclude the ceremony with the dragonglass wasn’t necessary to create ordinary White Walkers.
Also I don’t think we’ve seen Children of the Forest except in these long-ago scenes. (Correct me if I’m wrong.)
But wouldn’t it make sense that the Night King would be likely to be the very first WW?
Of course. I just didn’t catch that. Thought I missed something. I binge-watched all 7 seasons in a week. Cut me some slack! 
You’re wrong. They were present with Bran and Meera and the old Three Eyed Raven in the cave under the tree. They threw hand grenades at the wights and died right before Hodor did.
Interesting thing is, one of the present-day Children was the same one who created the Night King thousands of years before in Bran’s flashback. So they lived ~10k+ years and died saving Bran. I’m unsure if there are any left at all anymore.
In the link I provided above it re-hashes the scenes with the Children. I believe the one in question was Leaf.
And if you want other confirmation, the actor in that scene is the same one who plays the Night King.
While that was definitely a cavalry-arrives-at-the-nick-of-time moment we at least knew that Sansa had asked for help from Littlefinger and the Knights of the Vale might be on their way.
I believe that it’s been stated that it’s only possible to warg into animals. Bran can do it with Hodor because Hodor is simple-minded. (Ironically it was Bran who broke his brain with mental contact in the past, which is why he is able to do it now.) While Theon might be missing some things and is still a bit twitchy he definitely isn’t feeble-minded.
I don’t recall that it’s been explicitly stated in the show in so many words. However, the First Man victim and the Night King are played by the same actor, Vladimir Furdik, although it’s difficult to tell with the Night King makeup.
Yes, as I said above, the Night King at least can create White Walkers from living humans with just a touch.
It’s not clear how exactly a baby White Walker grows into an adult or how long it takes. Will we see Craster’s Last Son as a White Toddler?
They are present in the Cave of the Three-eyed Raven with Bran and Meera. Apparently all of the surviving Children are slaughtered when the Night King attacks the cave.
So the Children of the Forest are gone. I think the story is going to end with all of the magical, supernatural elements gone from this world. That probably means Bran is dead.
So how’d that whole White Walker thing work out for them? :dubious:
I think the irony is intended.
How would that be? We’ve seen people repeatedly resurrected by the Lord of Light. I don’t think Bran dying will have any effect on that.
That would be very Tolkein-esque of them. LOTR ends with that basic premise. The Elves are leaving Middle Earth and magic in the world is much diminished.
That’s exactly how the idea occurred to me.
As for that, it’s not that Bran dying is going to trigger that but that the story ending with the magic gone means Bran will be dead (or at least no longer the Three-Eyed Raven, but more likely dead). The Lord of Light will be gone, so no more resurrections. Just my guess, though.
I do seem recall it being stated wargs can only warg into animals, but I don’t think that rule applies to Bran. As evidence, if he could only warg into feebleminded humans, he wouldn’t have been able to lobotomize Hodor in the first place since original Hodor wasn’t feebleminded.
I suppose it’s possible that Bran can warg into any able-minded human but that human would suffer a similar mental breakdown as Hodor did, but the presentation indicated that Hodor’s mind was broken by the specific circumstance of being warged in the past to do something in the present. If Bran warged into, say, Tormund, just for shits and giggles (and because he’s big and strong like Hodor was) I would expect Tormund to be fine (albeit super pissed) afterwards.
I’m not seeing it. There really hasn’t been any background for such a broad ending. R’hllor and the Night King haven’t been set up as opponents in a mighty struggle for the world.
No idea who R’hllor is but as I said, this is just my guess.
As for no background for such a broad ending, the Night King has been said to want to create an endless night. This is literally a battle between good and evil for the future of the world.
The Lord of Light, worshiped by the red priests and whose champion is Azor Ahai, who was identified at one point as being Stannis Baratheon.