At first the scene at the end of the winter montage where Dr. Schultz and Django meet a marshal friend of theirs felt out of place. But after the Candieland sequence it makes sense. The marshal offers them cake, which they accept. At Candieland, there's constant mention of dessert (a cake), that Candie goes on and on about. When it finally appears, Dr. Schultz refuses it. Why? He likes cake, but he's absolutely disgusted by Candie. It also serves as a Chekhov's Gun for Django's escape and comeback in the finale.
Laura playing "Für Elise" — an instantly recognizable piece written by a romantic idealist who advocated for national and personal freedom, played in a slave owner's house. It seems that the Candie siblings both follow trends and like to play at being educated, but never get beyond the superficial.
The punishment Stephen has in store for Django is to rob him not only of his freedom, but his identity, his place in the world and his voice. For a man like Django, who has fought for so long for these things, this is truly A Fate Worse Than Death.
The moment where Schultz shoots Candie is actually the first time in the entire film any of the primary characters breaks the law. Sure, Schultz's method of acquiring Django was legally iffy, but he was very careful to observe the forms of the law, and they did some lying and deceiving to their own ends, but there's not really any crime you could pin on them. All of their killings were legally protected. Whereas Calvin, despite all the brutality, threats, torture, and murder, never did anything illegal, because everyone he killed or mistreated was his legal property. Every time lawmen are present, they have no grounds to do anything about anything. It's a brilliant commentary on how utterly twisted the laws of this time and place were. These characters, heroes and villains alike, are as violent and immoral as in any Tarantino film, but in this context, even the worst bad guy is technically an upstanding citizen.
Candie did break the law just before that by threatening the life of Broomhilda, who had just been granted her freedom.
That Mandingo fighter who ran away after three fights was killed by two dogs. Candie collected on the last two fights he was owed.
Django later avenging D'artagnan's death wasn't just for a one liner's sake. Upon returning to Candieland, Calvin asks how bad Stonecipher's dogs got her. If D'artagnan hadn't run as well, drawing the attention of Stonecipher and his dogs, Hilde would have been the one being torn apart by hounds instead of being brought back by presumably a few fellow slaves. In a way, Django probably felt like he owed him one, since he talked King out of saving him to maintain their cover.
If the theory that Stephen was only playing dumb in the presence of others is true, then consider the moment where Dr. Schultz says the word 'panache' and Stephen acts all confused — it's also evident that Calvin didn't get it either, judging by his expression and how he fields the reply so as not to look like he doesn't know the definition. It's almost as though Stephen got all over-the-top befuddled for Calvin's benefit.
On that note, pay attention to Stephen's hurricane of similes when Candie returns to Candieland. "I miss you like a baby misses mamma's titty" sounds like an innocuous and heartwarming line. "I miss you like I miss a rock in my shoe" is the last one he says. You wouldn't miss a rock in your shoe. Stephen might be the head house nigger and he might help Calvin out a lot, but that's a subtle clue he isn't completely content with his lot in life.
Schultz telling Django to keep the bounty note in his pocket came in handy later.
Upon finding out that Schultz and Django have been putting on a facade, Calvin gives a lesson on the biology of slaves as a way of saying "so you thought you could outsmart me, but you couldn't, 'cause I'm white." Of course, who was it that actually figured out they were being lied to? Stephen, a slave.
It's also a brilliant Viewers Are Geniuses moment: what's the science that Candie uses to disparage Django and Broomhilda? Phrenology. Phrenology, for those that know, is a pseudo-science that even before the events of Django had been disproven as complete bullshit. So not only is Candie wrong on the "black brains are subservient to white brains" garbage, he's also an idiot by his own time period's standards.
Recall Schultz's story about Broomhilda: the king locks her up, puts her around a dragon, and so Sigfried comes and kills the dragon and rescues her. Pay attention: Sigfried does NOT kill the king. He kills the dragon. Just like Django doesn't kill Candie; he kills Stephen.
What are two Australians doing in the Antebellum Deep South? One of the first large immigrations of Australians to the US were miners who came to America for the California Gold Rush. Those two were probably former gold miners who moved on after the gold was all mined.
When Django first arrives to Candieland and sets at the bar, you may notice the house slave sitting at the bar immediately takes her drink and moves across the room. If you remember Django's earlier words; there's nothing lower than a black slaver.
Django's status as The Quiet One makes sense when you consider that even as free man, white southerns still view him with contempt due to his race. The only person he speaks to on equal terms throughout the movie is Schultz and possibly Schultz's marshal friend.
Stephen makes it adamantly clear to Calvin that he wants Django's bed, sheets, pillowcase and everything else burned after he leaves. He gets his wish.
When outlining the plan to rescue Broomhilda, Dr. Schultz uses the analogy that instead of offering to buy a horse, they should offer to buy a farm. He winds up "buying the farm."
According to Stephen, the Le Quint Dickey Mining Company kills their slaves when their backs give out, then tosses them down a hole. One of the miners is Quentin Tarantino in a cameo. So, unlike Jimmie, storing dead niggers is his business.
At the end of his encounter with the Speck brothers' slaves, Dr. Schultz has provided not only their freedom, but given them a weapon (one of the brothers' rifle), some cash (the money he "paid" for Django), and a general direction to head in. Dr. Schultz not only treated these slaves with respect, he gave them a more-than-decent shot at making it to a freer future. Really drives home how much he hates slavery and how much he's willing to do for those under its bondage.
Billy Crash is about to castrate Django to death before Stephen comes in at the last second to say Lara Lee has changed her mind and decided to sell Django to the Le Quint Dickey Mining Company. Billy remarks he should have been told earlier and Stephen simply gestures. Likely because he was standing out of view the whole time and waited until the last second to torment Django.
When they come across the slave in the tree who tried to run away, as Candie steps from the carriage you can see he is stepping onto fresh soil, probably turned over, as if it were dug up for a grave. You also notice another one not too far from the one he is stepping on. Later, when Django is chained, Stephen lists all of the things they've done to other slaves; one can only wonder what happened to the two people whom we know are in the ground.
At the end of the film, Django and Hilda successfully kill all the owners and overseers at Candieland before running away. One can only imagine the reaction that must've occurred throughout the South at the thought of a slave rebellion going that far.