Hriston
Dungeon Master of Middle-earth (He/him)
I think Celebrimbor already has the idea of rings of power in his head, --that's what the forge is for-- but I'm pretty sure he's not Sauron. I think it's unlikely that the creepy three encounter any of the major characters in the next episode other than the Stranger, Nori, Poppy, Marigold, and Sadoc. No one else is anywhere near Mirkwood which is where the Stranger, who they're following, is headed.I assume it's the creepy three finally speaking.
I would guess it's either someone in Lindon putting the idea of magic rings in folks' heads, or Halbrand.