Jack describes the newly-revealed area as a "church of necromancy" where demons are raised from Hell. Necromancy concerns the dead, not the summoning of devils.
When the demon falls into the hole in the stone floor, the walls visibly bounce.
Johnny is in his apartment at 11:17 at night, listening to a baseball game on the radio. Baseball games don't play at 11:17 at night.
Normally they don't. However, some games go into extra innings and could potentially end late hours of the night. Another reason may be the game was playing on the West Coast, which would be a few hours behind the city he lives in.