First things first : please excuse my bad english, i’m not a native speaker.
If we assume that all the 9 Runelords (the big Seven + Xin + Alderpash) wake up, one way or the other, I think they will split into two team, a very strong one and a “weak” one.
I don’t think Xin will ever agree to work with Sorshen, Xanderghul or Alderpash. Because, well, you know : they killed him ^^
Same thing : Alaznist and both Karzoug and Alderpash cannot be on the same team (K & A hate each other deeply and there’s no such thing as two runelords of Wrath in the mind of a… runelord of Wrath !)
So, I think we will have a major team (with Sorshen, Xanderghul, Karzoug, Alderpash, Krune and Zutha) and a “minor” team (with Xin, Alaznist and Belimarius). Because, of course, Belimarius would side with the team in wich she could be the most important.
The big team can also count on Fafneir (ally to Xanderghul), Ungarrato (mythic undead barbarian with a sword of sin : yes please !) and perhaps the Oliphaunt.
And the “small” team can count on Xin-Undoros, the use of the Sihedron and, I think, the help of Ayandamalha (to kick Sorshen in the teeth, obviously).
In my opinion both Kazavon (because stuck between the two and weaker than both of them) and the Storm Tyrant (because Rune Giants) will be forced to join one of the two Thassilonian team.
One side question : who will be trusted with the other Swords of Sin (beside Ungarrato) ? Because a strong fighter with one of those artifact is a huge asset for each team.