i lost all the main characters as in, they are despawned (cant find em in the castle.) and cant change my formation. (just downloaded the new update today.)
If you enter and leave an area where your party is split, like the bathhouse in Aldlyn, it should reset the party and give you back and lost party members.
What did you do before they disappeared? Did you lose them after leaving the time skip phase? Or some other event or area where the party was changed?