Is there anywhere that lists progress, and what to do? It feels like an open world, but I don't know what structure there is to anything, so I don't know if I'm missing out on anything. I've been following forever, so I think I have done everything so far, but I'd hate to miss out on some storyline or scenes!
Look through your Inventory and press the Logbook, obtained Via the abandoned Warehouse where Cassie is.
Secondly in the Slum market in New Ark a fortune teller simply interact with the "!" and you will find her.
And nearly every named NPC has a storyline set in already, they are all quite lengthy so get the Logbook to get the unfinished task, and finished task list.