Several characters in this book stick to their historical script, which means that they don't kill vampires or get killed by vampires. (Mostly they die of fever, would be our guess.)
But that doesn't mean these characters are unimportant. Each of them helps shape Abe or pushes him towards some milestone. (But that's still not as exciting as fighting vampires.) And each of them is based on a real figure from Lincoln's past.
James Gentry and Denton Offutt are both businessmen who admire Abe Lincoln's hardworking nature and they both hire him for some job that helps place him in the world. Gentry hires Abe to raft down the river (with Allen Gentry, James's son), which gives Abe the chance to see more of the country, especially the Southern (slave) states and New Orleans (4.22). It's when Abe is off on this trip that he starts thinking about vampirism and slavery.
Denton first hires Abe for another river trip, but then hires Abe as a clerk in his New Salem store (5.34, 5.45). So that's why Abe settles in New Salem. And we suppose it would be accurate to say that Abe only goes on with the rest of his life because Offutt's store fails.
We could add William F. Berry to the list of people with whom Abe works. Abe and Berry open another store in New Salem. But Berry is a drunk and Abe gets a lot of debt when this store fails (6.40).
So we could sum up these relations by noting that Abraham Lincoln was a hard-worker, but was clearly not destined to be a great businessman, even though business relationships helped him explore the world.
Abe didn't get a lot of schooling, but his teachers and partners really helped him develop his intellect. At the very least, they loaned him books. For instance, the awesomely named Azel Waters Dorsey is an early teacher of Abe, but we hear very little about him because young Abe Lincoln doesn't spend a lot of time in school (1.45).
Later in his life, in New Salem, Abe becomes friends with another schoolteacher, the conveniently named William Mentor Graham (5.47). Abe may be too old to go to school (imagine how silly he would look crammed into one of those tiny school desk/chair combos), but Graham loans him books like Kirkham's Grammar. It's from those books that Abe learns a bit more about being a great speaker, writer, and thinker. (And let's add, Graham introduces Abe to the first love of his life, Ann Rutledge. Bonus!)
Lastly, let's add John Todd Stuart to this list of people who teach Abe or encourage his learning. Abe meets Stuart when they are in the militia for the Black Hawk war in 1832 (6.32), but Stuart's real role is to encourage Abe to get a law degree, which he does in 1836. Though, let's be clear: Stuart may be encouraging, but Abe gets this degree after studying all on his own, without even Shmoop to help him (7.11). Curiously, Stuart's other main role in this story is to introduce Abe to the second love of his life, Mary Todd. One might even say that love and learning go together for Abe.
Abe is also helped out by another law partner/teacher, William H. Herndon, who doesn't introduce Abe to any women and so is less important (8.106).
To sum up, Abe didn't get a lot of formal education when he was young, but people throughout his life encouraged him to learn (and introduced him to women).
When Lincoln is president, he's also the leader of the US military. Funny how that happens. That means, of course, that he has a spot in history, and that he'll have to meet some historical folks, too. Several characters in the book play pretty much the same role they played in history, playing some pivotal role in Lincoln's life (or death).
Take Allan Pinkerton, for example, who worked as a bodyguard for Lincoln (10.167) and never learns about the vampire menace.
General George B. McClellan plays a slightly more important role in Lincoln's life, though in this book he hardly shows up. McClellan is important because (1) he's a terrible general, who makes a real big mess of the Civil War; and (2) he's politically opposed to Lincoln and runs against him (and loses) in 1864. So McClellan's role in history is as a screw-up. Thanks to him, the Civil War takes a lot longer to win; but also thanks to him, Abe Lincoln gets a chance to win it.
Two other men in uniform (though different uniforms) play important roles in Lincoln's assassination (which is a job McClellan would probably mess up): (1) the Washington policeman John F. Parker is the drunk who isn't very good at guarding the Lincolns. He's the guy who abandons his post and lets Booth through (13.58). (2) Major Henry Rathbone and his fiancée Clara Harris (13.57) are the couple who have the misfortune of being in the box at Ford's Theater when Booth comes to kill Lincoln. Rathbone can't stop Booth, but he does grab him for a moment, which is more than Parker did.
William H. Seward (Secretary of State) and Lincoln's other Cabinet members get only a little time here, which we think is appropriate. Would you rather read about Lincoln fighting vampires or Seward wrestling with bureaucratic paperwork?
But what makes these Cabinet members special is that they get told about the vampire menace (unlike the characters who are purely historical). But they don't all believe it. So we get to see the Cabinet so that we can see how important, powerful men react to the idea of a vampire enemy. Here's how they react:
Seward (Secretary of State) actually already knows about the vampire danger. In fact, according to Henry, Seward is probably the second-best vampire hunter in America, killing almost as many vampires as Abe. Abe's reaction? "Abe had to bite his lip to keep his jaw from dropping. Bookish, privileged little Seward—a vampire hunter? Impossible" (9.93). So Seward knows about the vampire menace, everyone thinks he was going to be the presidential nominee in 1860, and he's also a strong abolitionist like Lincoln—but it's just not his destiny to be president.
Gideon Wells (Secretary of the Navy) reacts with silence to the news about vampires (11.27).
Salmon Chase (Secretary of the Treasury) thinks that Lincoln is making a weird joke (which is funny coming from a guy named "Salmon") (11.27). Later, Salmon sees the sense in issuing the Emancipation Proclamation, though he still doesn't believe the freed slaves will rise up against vampires… because he doesn't believe in vampires (12.35).
Edwin Stanton (Secretary of War) believes in vampires but has trouble understanding why Jefferson Davis and other humans would work with them: "Why would Davis... why would any man conspire against himself? Why would any man hasten his own enslavement?" (11.28). And when Lincoln is assassinated, it's Stanton who is in charge of catching and killing the assassins, whether they're vampires or not (13.93).