As I live in close proximity to neighbors and have young kids, I empathize with your situation.
I know it's evil, but I have mixed many times on headphones out of sheer necessity. I've found the AKG 240 series headphones to be the most "monitor-like"... pretty flat. I've found the Sony 7506s to be good also, although they sound more like a home stereo, they have a bit of a bottom and top end boost. But both will work in a pinch. And no, they are no substitute for decent volume on monitors. Some things will get skewed. You'll probably mix things that are dead center too loud, and good luck getting the bass right. But still, it's been done before and if it's your only option, no sense in giving up because of the "prevailing wisdom."