1)
Why does it say "Lifnei ha'Melech b'Cheser Malchus"? Would she not wear the crown even before she comes in front of him?
1.
Malbim: Indeed, she would not. He wanted to show that she is not queen due to herself, only because he married her.
2)
Why did he want to show her beauty to everyone?
1.
Malbim: This was to prove that he married her only for beauty, and not because she inherited the kingship. If he married her for kingship, he would take her even if she was ugly. Also, if would disgrace the kingdom to show her beauty, as if this is more important than the kingship that he attained via her.
