Assuming that the minimum number of characters is 4, I will only say three lords of each faction and I bet a black leg Estalian ham that I hit all of them:
Arbaal the undefeated
The masque (FLC)
Egrim Van Horstmann
The Blue Scribes (FLC)
I think these characters are guaranteed, which is good news. Although I will miss a lot:
Valnir the reaper, but I think Glotkin and Tarmukhan are more popular so he will be forgotten.