Halfway down the hill after the church there used to be a bakery that stayed open. Was gone the last time I looked.
Many of the shops that used to open have gone. The bakery in Tremblay-les Villages used to open, and had a cyclist dummy with turning wheels in 1999, now it's a house. Another factor is the earlier start times on a Sunday. Bakers work early hours, so it's not much of a leap to open at night.
There's some discussion of lights and group behaviour on facebook. I can only spot one hand signal at 1.11 in the film. Another interesting point is the way that very bright, and poorly aimed lights project shadows onto the wall of the church.
The riders in the middle of the groups with no lights would be unaware of the fact. Those without fluorescent gilets would be reluctant to drop out of groups. They'd have the chance once the groups split on the climb out of Longny.