One Big, Happy Family
In addition to Billy and Freddy, the Vasquez household includes foster children Mary Bromfield (Grace Fulton), Eugene Choi (Ian Chen), Pedro Peña (Jovan Armand) and Darla Dudley (Faithe Herman), although not all of them can be clearly seen in this brief sequence.
Long before the likes of Superboy and Supergirl, Shazam had his own spinoff characters, with the likes of Mary Marvel, Captain Marvel Jr., the Lieutenant Marvels, and even Hoppy the Marvel Bunny, Known collectively as the Marvel Family, and in more recent years the Shazam Family, they were each imbued with a portion of Shazam's powers. In DC's New 52, Billy could share his powers with his foster siblings, each of whom then possesses additional unique abilities. However, there's no indication that will happen in the film.
Spanning the Globe, From Metropolis to ... Gotham
As with the previously shown pieces of Freddy's collection -- the "authentic" bullet fragment, the replica Batarang, etc. -- these newspapers firmly establish Shazam! in the same world as Man of Steel, Batman v Superman: Dawn of Justice and Justice League, even if it doesn't possess the same tone.
In addition to the headline questioning Superman's "real agenda," presumably a reference to congressional hearings, there's also a nod to Lexcorp, and a copy of the Gotham Free Press.
Please Let Fawcett Central's Mascot Be the Tigers
Billy and Freddy attend Fawcett Central, a nod to Fawcett Comics, the original publisher of the comic adventures of Captain Marvel (aka Shazam) and the Marvel Family. A copyright-infringement lawsuit by Superman publisher National Comics, as DC was then known, contributed to Fawcett ceasing the publication of all Captain Marvel-related comics in 1953.
Nearly two decades later, DC licensed those character, along with Bulletman, Spy Smasher and other Fawcett characters), before eventually buying them outright, and integrating them into its own superhero universe. Beginning in 1985, Billy Batson and others were based in Fawcett City, a tribute to their original publisher.
Next Stop ... Well, Not 30th Street Station
Although filmed primarily in Toronto, Shazam! is actually set in Philadelphia, again owning to the hero's New 52 reboot. As Billy flees the bullies by entering the subway station, you'll note signs for SEPTA, the Southeastern Pennsylvania Transportation Authority. Billy is poised in the trailer to exit at 30th Street Station, the city's primary railroad station, but it doesn't quite work out that way ...