In terms of numbers to cut, there are a few redundant songs here and there (the Friends of the ABC, for instance, I expect will have a significantly reduced presence). The epilogue, too, probably could stand some trimming (one song that springs to mind, even though it's a great song on its own, is "Empty Chairs at Empty Tables", which is like five minutes of Marius singing about how his friends are dead and he's sad about it; I'd probably limit the Thenardiers to only one of either "Dog Eat Dog" or "Beggar at the Feast").
Well, aside from "Red and Black" but I'd hate to see that go too. 
