Are hard boiled eggs dangerous to eat if they have some green color from being overcooked?
Not at all. It's not a sign of spoilage; it's just that they've been overcooked a little. I haven't heard the part of losing nutritional value; not sure it's true.
They are not dangerous. However, when attempting to overcook the eggs, they tend to lose their nutritious value and nothing will be gained from having them.
Not at all, just serve them up with some ham Sam I am.