Welcome aboard:

Just Thought of a great way to incorporate plot characters with player characters.

The plot characters can be a vital part of the main quest line and would be interactable with the players via main quests. Some of them can be part of the crew of the ship that crashes on velani. They can take charge of the situation and take a confusing and dangerous situation of crashlanding in the velani deserts to guiding the group to the town and interracting with the villagers. I think the players can be a secondary role in the plot more on the lines of following the main characters around vs being the main characters. That way the player who is playing wont have the plot to assume the player has a certain personality.

Yeah, that sounds pretty reasonable.