Eeeeh, I feel like there'd be a little more warmth involved. Sector 5's church has always been depicted as right at the edge of the plate, so it gets the most natural light of any place in the slums besides Aerith's house.
I'm more inclined to think this is the last tunnel before Avalanche breaks through into Sector 8. Vyzz pointed out the wiring, which close to the kind used in the service tunnels.
Most likely President Shinra's Office (heavily redesigned)
Either the collapsed tunnel after the reactor 1 explosion or the hole leading from sector 5 to the destroyed street in sector 6
Remember that the theme of this exhibition is "Farewell Stories", which means all of those 8 pictures should represent a link to someone or something dying or perishing. In this case Aerith, President Shinra, the Avalanche members and Sector 7 with its inhabitants.
I'm not sure how the debris riddled hole and the sewers tie into this theme, though. If that hole really represents the one leading from sector 5 to 6, it's at least tied to Aerith. With the sewers, however, I'm at a loss. Unless we're misinterpreting that one.