So I finished the main quest about find the Ambitions, fought the waking flames high priest... and then the story seems to drop off with the 4th Ambition still out there somewhere. Am I just missing a quest somehwere, or did they just leave it open-ended for how?

Also how does Fargrave tie into this? Is it part of the storyline or just extra side-quest content? I didn't get a message or npc telling me where to go to get to Fargrave except for that brief dialogue from Lyranth at the start of the expansion...