Some Lavi-centric DGM AUs
-Final Fantasy X AU where Road is a Summoner and Lavi is her Guardian, but Road believes in the old ways of Summoning from back during the Machina War rather than worshipping Yevon which she thinks of as a false faith. Lavi personally doesn't care either way, he just sees Yevon as another form of control over the masses. Before Road was Summoner, it was Mana and Neah. Mana became the Final Aeon and is now the new incarnation of Sin.
-Wolf's Rain AU where Bookman and Lavi blend in with humans by running a library in one of the domed cities. Lavi and Bookman are some of the only wolves in the world that can actually read. Kanda is a street wolf that acts as a mercenary doing odd and dirty jobs and comes to Lavi's library to get information. Lavi usually pisses him off by teasing him to read up on what he wants to know (because he knows Kanda can't read just like most wolves). Their library gets visited often by a human girl called Lenalee who comes in to pick up research material for her brother. Lavi likes her but keeps the fact he's a wolf a secret from her because he thinks she'd never want to speak to him again if she knew, and might even turn him in to the Nobles. Allen is a flower maiden probably.
-Last of Us AU where Bookman and Lavi's family are tasked with gathering information on how the world has changed as a result of the Infection. They travel around everywhere, talking with different groups both good and bad, learning all the different ways people are finding to survive. Part of their mission is to find and report on people who are immune to the Infection.
-War AU where Lavi is a younger (like pre-teen) intelligence thief and courier, infiltrating battlefield lines to get sensitive information for whoever will pay or feed him enough. He's quick on his feet and almost too smart for his age. I imagine him being kind of like a young Nathan Drake from Uncharted 3 (see chapters 2 and 3).
-Wolf Children AU where Bookman and Lavi move around a lot becuase they're werewolves and Lavi is absolute crap at keeping it hidden for very long no matter how many times Bookman reprimands him for it.
-Criminal AU where Lavi has split personalities, one "Lavi" and the other "Junior". Lavi is generally warm, bubbly, and only playfully mischievous, but he gets really anxious about a lot of things and worries about being accepted and generally doesn't go after a lot of things he wants. "Junior" is way more dark and cold, a pyromaniac/arsonist that generally doesn't give two shits for anyone and just takes whatever he and/or "Lavi" want without much regard to anyone. Both sides are aware of each other but "Lavi" tries not to let "Junior" be in control whenever he can help it. He doesn't stay anywhere very long because of "Junior" doing really bad things when he's in control, making it difficult for him to maintain any kind of relationships with people.
-Assassins Creed AU where the Bookmen Clan are a third neutral side between Assassins and Templars, some of which are genetically the closest things to the Isu/First Civilization that still exist in the modern era, tasked by the First Civilization (Juno, Minerva, Jupiter, etc) to guard history's flow and the Pieces of Eden. "Junior" is just the latest of many past Bookmen and as a result of having used the Animus too many times, suffers severe consequences of the Bleeding Effect and an identity crisis between "Junior" and all of his descendents whose lives he's relived.
-Medieval Centaur AU where Lavi and Kanda are centaurs who help make up the kingdom's cavalry. Lenalee and Allen are humans. For reasons no one talks about, Kanda doesn't partner up with anyone during battles, fighting solo and giving rides to no one. Lavi however has no problems partnering up and loves to give all the ladies rides across the countryside in his spare time. Lavi's favorite girl is Lenalee, though its just as often he sees Road who's more often than not vying to get his attention on her to have some fun. Allen gets partnered up with Kanda and stubbornly gets it in his head that he's going to earn the right to ride with him into battle. Kanda is completely not-okay with this and tries to make Allen's life ten times harder than it has to be in the meantime.