So... Since we were opening up the game, we decided to invite Firstborn's other close friend from school as well. He's a bright kid, and this seemed like it would be right up his alley as well. So he showed up on time, and we seated him at the table, and...
He's never played Dungeons and Dragons before. At all. Or anything like it. Tabletop roleplaying games are a whole new world to him.
So... I asked him what kind of character he wanted to play, and told him that we could really use a tank - somebody to stand in the front line and keep the bad guys off everybody else. I also had him look at a bunch of the DnD figurines and see what appealed to him.
His first choice was a wizard, but when I remarked that was probably the most complicated thing we could try to create, he shrugged and said he liked either magic or stealth. Well, all right: it won't hurt to have another rogue in the party, and at third level he can opt for Arcane Trickster and have some spells to go along with it.
This turned out to be a really good choice, since I was already getting a headache from trying to build things quickly in a system I don't know all that well while school-aged children cavorted around me. Better still, he liked the idea of playing a small race, and we quickly settled on a Lightfoot Halfling. All of that, it turns out, is not only in the core rulebooks; it's also in the SRD. So the player of the Mousefolk Cleric stepped in, pulled up something called DnD Beyond (which appears to be a set of online resources from Wizards of the Coast, but I'm still catching up from when I stopped at Third Edition), and made him an online character sheet that he could access from his cell phone in about three minute flat.
So the party began the campaign with two rogues, a dragonborn sorcerer, and a mousefolk cleric.
We didn't spend a lot of time on his backstory, but I made a quick directorial decision that his was the only character who had grown up in Roslof Keep (or the town outside it, anyway) and that he had a brother who was in jail, and that he needed money to get his brother *out* of jail. He just nodded and went along with it, and then played up the character as a wide-eyed innocent who just wants to be friends. The Cleric is suspicious that he's not as naive as he seems, but then the cleric is suspicious of most of the rest of the party, and not without some reason.