Floating an egg determines if only the egg is old or new. Freshness is only determined by breaking the egg and testing the odour.

Sure, but when pealed shall there be wastage. Naturally(nonrefrigerated) egg is ready to boil only after 3 days.

Not necessary, an egg can last for 40 days in 35*deg. A pack of 30 eggs if consumed one at per day, we will be left with nothing in few days. Always buy fresh eggs for consumption.

Up to 3 eggs per day per person is acceptable. https://www.healthline.com/nutrition/how-many-eggs-should-you-eat#section3