2. I'm a fairly sure that Lyanna Stark is also the knight of the laughing tree (and that's part of the reason Rhaegar loved her so much it caused a civil war).
3. in King's Landing there is a black cat with one ear who hates Lannisters . I am suspect that he was Rhaenys Targaryen's pet whom she calle Bellarion the dread. I also suspect that Arya Stark will see through that cat's eyes.
4. I am fairly confident that the horn of Joramun was found by John Snow with obsidian weapons and given to Sam Tarly
5. I am quite confident that the younger brother of Cersei who will strangle her is Jaime not Tyrion.
6. of course John Snow is one of the heads of the dragon. I guess that Aegon Targaryen VI isn't the third (he would appear in the TV series if he were important). Some suspect that Tyrion is the bastard son of the mad king. I don't have a guess. Also Brandon as warg might control a dragon.