For the pickled peaches: Combine the maple syrup and vinegar in a nonreactive medium saucepan and bring to a simmer over low heat. Stir in the peaches and cook until soft. Remove from the heat and let the peaches sit in the liquid for at least 15 minutes. Remove the peaches with a slotted spoon to a small bowl. Reserve the cooking liquid for the caramel.
For the pickled peach bourbon caramel: Cook the reserved pickling liquid over high heat until reduced to about 1/2 cup. Add the maple syrup and butter and cook until slightly thickened, about 5 minutes.
Remove the pan from the heat, add the bourbon, carefully return the pan to the heat, bring to a boil and cook the alcohol off, about 5 minutes longer.
For the cream cheese filling: Whisk together the cream cheese, mascarpone, peach preserves, honey and cinnamon until smooth. Cover and let sit at room temperature while you make the French toast.
For the French toast: Preheat the oven to 300 degrees F.
Set a baking rack in a rimmed baking sheet. Spread out the bread in a single layer and bake to stale, about 15 minutes. (Alternatively, slice the bread the night before, place on a baking rack set on a baking sheet and let stale on the counter overnight.) Remove the bread and let cool. Increase the heat of the oven to 350 degrees F. Set aside the baking sheet and baking rack.
Heat the oil in a small pan over medium heat. Add the bacon and cook until golden brown and the fat has rendered, about 10 minutes. Remove the bacon to a plate lined with paper towels.
Whisk together the eggs, yolks, granulated sugar, vanilla, cinnamon and salt in a baking dish until smooth. Whisk in the heavy cream, milk and bourbon until combined.
Heat 2 tablespoons of the butter and 2 tablespoons of the oil in a large nonstick saute pan over medium heat until it begins to shimmer. Dip 4 slices of the bread into the custard mixture and let sit until soaked through, this should take at least 1 minute per side. Remove the slices with a slotted spatula and let the excess custard run off. Place 3 or 4 slices in the pan at a time (depending on how large your pan is) and cook until the bottom of the bread is golden brown, about 3 minutes. Flip over and continue cooking until the bottom is golden brown and the center is cooked through, about 3 minutes more. Transfer to the prepared baking and place in the oven. Repeat with the remaining butter, oil and bread. Bake the French toast in the oven for 5 minutes.
Remove the French toast from the oven and spread the cream cheese filling on 4 of the French toast slices, Top with the remaining 4 slices and transfer to plates. Top with some of the pickled peaches, drizzle with the bourbon caramel and garnish with some of the bacon. Dust with confectioners' sugar and garnish with mint sprigs, if desired.