children of the night are night dwelling creatures. trypically in todays society they're talking about vampires, but it can be a werebeast, or a simple creature like a bat or owl.
indigo children are real, they're people with old souls if memory searves. they're smarter than other children their age and act more mature than children their age. personally, while i don't deny their existance, i find it very 'New Age' and therefore to me corney. there are indigo children on SoM, poke around, you'll find some. children of the moon i'm not sure about though.