Honestly I have Erenville pegged as the fourth claimant. Hiding under a different name/identity, has known Wuk Lamat since they were children, is obviously being evasive and trying to distance himself and...
If the poster composition is anything to go by, it would be so neat and clever for the four claimants to be arranged like this: hidden in plain sight.
Like most people here I think Thancred and Urianger were petitioned by Koana, who would seem the perfect type to be seeking the help of Archons given his background. I feel like the succession war will be over fairly early on, especially if Valigarmanda
is the first trial.