Doesn’t that make it even more weird that they put them so close together? Narratively speaking?
Not for me. The reason those tiefling refugees are traveling is directly connected to the prequel tabletop adventure, which also takes place in Avernus. There is a connection there, so I don’t find that thematically odd.
And I’m pretty sure that the forces you face on the ship are cambions. A cambion has an infernal parent while a tiefling has a more distant infernal ancestor.
