5. The fire motif was hugely significant
Throughout the series Daryl and Carol have continually been surrounded by fire: we know Daryl's mother died in a fire, the CDC exploded in season 1, the farm, the prison, Beth and Daryl's cabin all burned, and lastly Terminus also went up in flames.
During their stay at the temporary housing center, Carol spoke to Daryl about her past and mentioned the person who she was with, Ed, "got burned away" and she became happier. Carol was surrounded by smoke a lot: smoke from the prison, and the plume of smoke from the still burning Terminus. Carol has obviously grown a lot through the series and like a phoenix, has rising from the ashes to become this new, stronger, happier person.
On the other hand, Daryl isn't quite done shedding his past, though we see him trying to move on throughout the episode, especially when he takes the copy of 'Treating Survivors of Childhood Abuse.' Despite this, he still has a long way to go, and in contrast with Carol being surrounded by smoke, Daryl was surrounded by flames; the notebook and dumpster he sets on fire to distract the walkers, the cigarette lighter he uses, and he was also the one to make the funeral pyre to burn the body of the child walker. Even though Daryl has a while to go before he can get "burned away" like Carol, he did note, quite poignantly "we ain't ashes.