Euron, not Victarion.
What we know about next season:
There will be a bran tree style flashback, either the Tourney at Harrenhal or just Young Ned/etc, won't expect it to be subtle like the books, basically it will confirm Jon's parentage
Randyll Tarly and family are cast, ie shit in the reach. We'll know next episode if Sam and Gilly are headed there, but since they've also cast Euron then I expect Balon dies (off screen) and Euron the new king of the iron islands will raid the reach like they do in the books.
As book readers these were the last little plots that were just beginning at the end of Dance. We don't know where they will go. So yeah, a small portion of the first few episodes we'll have knowledge off. But like 95% of season 6 will be entirely new territory. There really won't need to be 2 threads. But i'd suggest keeping them, just so the "shit happened differently in the books" is kept to a minimum, but basically everyone can just start posting in the no pussy shit thread since we ain't gonna know shit anyway.
Unless of course Winds is released first, but fat chance of that happening.