does that mean in guardhog au, shadow is infinite's uncle lol
The family tree in Guardhog is honestly insane, at least when counting found family/artificial creations.
Like you start with Black Doom, father of all "purebred" Black Arms ever and Gerald Robotnik, grandfather of Maria and Ivo Robotnik, teaming up to create Shadow who ends up being like a little brother to Maria. So Shadow is immediately both Maria's uncle and her brother.
Shadow goes on to have one of his eggs fertilized by Tails and incubated inside Sonic's womb. That egg hatches to become Hoshi "Vampire" Prower (Middle name was Sonic's idea after he learned the hard way that Hoshi prefers bloodletting to breastfeeding).
At one point Eggman kidnaps Shadow and Cubot, hitting buttons without thinking, gets "given" some eggs from Shadow, with Eggman keeping one of them to study and eventually hatch into Eclipse.
Maria lays an egg in a dying Jackal mercenary that hatches to become Infinite. Infinite later lays an egg in his partner (Undecided on who, definitely a hedgehog, might be an OC) that hatches to become a (currently unnamed) child.
Hoshi and Infinite's kid eventually have an enemies to lovers arc and become Silver's parents.
There's absolutely no inbreeding, but if you count found family/artificial creations there's technically lots of incest.