Having an Eldar army all the same colour, across Aspects as well, does work. Thankfully, Eldar Aspects, bar Dire Avengers, all look very different from afar. Dire Avengers are simply tarty Guardians.
If you are gonna do the same colour scheme across all units, definitely avoid what I tried back in the day which was adding touches of their default Aspect colour, as this ends up complicating the army's overall look and can look messy.
As for bone and red, I know it so well as my Eldar were also bone coloured!!! Who'd have thought?! When painting bone, don't ever start with a black undercoat - it's a noob's mistake. Can you imagine painting a Falcon from a black undercoat up to Bleached bone? It would take forever, need a million coats of each colour and could still look messy. I started from a white undercoat, Bleached Boned the entire model with maybe two coats. Then went into the recesses and shaded areas with thin Snakebite Leather (or other suitable brown), and then highlighted with white. Quick, simple and looked really good.
It'll obviously prove an issue for the dark red areas, but a quick base of black on those areas, or even keeping them separate (like helmets, weapons, Dire Avenger loin cloths?) and then sticking them on later would be a good idea.