Plot Holes in the Book of Esther

Why wasn't the first party co-ed?

Why didn't the Greeks, Persia's traditional rival, take over the kingdom when everyone important was partying in Shushan?

Why didn't the king blink when Haman asked for permission to murder millions?

Why didn't the King take Haman's bribe? After throwing all those parties, he didn't need some spare change?

Why did Haman need to build a gallows for Mordechai? Couldn't he just hire the firm of Two Guys Named Vito to settle the score quietly?

Why didn't Esther accept the King's offer of half the kingdom. He made it twice, so we can assume he was serious.

Why did Esther drag Haman and the King to a second party? Couldn't she have ratted out Haman at the first party?

Why did Charvonah have such a big mouth? And if he had it in for Haman, why did he wait until the last minute?

Why did Mordicha get Haman's job? What were his qualifications? Is that how it worked in Persia? If someone plotted to kill you and your people, did you automatically take his position when the plot was foiled?