Fridge Brilliance: Otto's presence at the eating competition of "Around the World in 180 Bites" is a joke on his drug usage, particularly how smoking pot gives one the "munchies".
Fridge Horror: Remember in the last cutscene where Bart threatens to toss God's memory card into the ocean far below? Note that it said "Planet Earth" on it. Had Bart actually done it, he might have unknowingly destroyed Earth and ended humanity as we know it.
Not really, he would just erase a savegame of a minigame of a game. Remember, God is a character in Ralph Wiggum's game, who in turn is a character in the player's game... cue Mind Screw
Fridge Horror and Fridge Brilliance here. In the final level up in heaven you Fight a myriad of people you've already fought before, as lampshaded by Comic Book Guy. Why? Because you already killed them before, and they're in heaven now.
Fridge Horror as you see those loggers walking around? So in taking down the factory, Lisa killed dozens of ordinary people. COULD be Fridge Brilliance: as the logger mentioned, his father and grandfather and great-grandfather were all loggers - maybe you were just taking down their Heaven-based ancestors?