They made a rather big deal about it earlier this season, after Daryl slammed the truck through the wall and Negan rejoined the main group inside Sanctuary. Eugene tells the Savior leaders he has a plan, but it will require a lot of ammo. Negan asks Eugene pointedly about his ability to produce more ammo at his little factory outside Alexandria, with the implication being that the Saviors are going to be very low on ammo post-escape. This seems to be completely forgotten in the ensuing episodes. Maybe it will still factor in somehow in the second half of the season, but they don’t seem worried about it.
The person in the vision in the end was definitely a sight gag, based on Carl’s vision of the future. In Talking Dead, they interviewed Chandler Riggs and he comes right out and says that the future stuff was Carl’s vision, that it’s Carl projecting the idea of everyone living together, working together to make a better life. Doesn’t matter that that last scene was out of sequence with Carl’s demise, as the whole episode was jumping around like crazy.