Short answer
A small blood spot comes from a ruptured vessel, the white cord is a chalaza holding the yolk centrally, and a cloudy white often contains carbon dioxide that has not yet escaped. None is a developing chick.
Blood and meat spots
A small vessel can rupture around ovulation or egg formation, leaving a red spot on the yolk. A meat spot may be altered blood or a tiny piece of reproductive tissue. Grading removes many examples, but home-flock eggs may show them more often.
The chalaza is structural
Two twisted cords of dense albumen suspend the yolk within the white. They are normal and edible. Prominent chalazae are often easier to see in a relatively fresh egg and should not be confused with an embryo or parasite.
Cloudy and thin whites
Cloudiness often comes from dissolved carbon dioxide and can be associated with freshness. As carbon dioxide escapes, the white becomes clearer and gradually thinner. Neither appearance is a safety test, so shell condition and storage remain important.