If an effect tells you to flip multiple coins at once and you haven't flipped one or more coins already during that turn, Edgar's last ability modifies that set of flips. For example, suppose you control Edgar, King of Figaro and Ral Zarek and you activate Ral Zarek's last ability ("−7: Flip five coins. Take an extra turn after this one for each coin that comes up heads.") on a turn where you haven't flipped any coins yet. Edgar's last ability will apply to each of those five flips, meaning they'll all come up heads and you'll take five extra turns as a result.