1)
Why did they bring the king to Beis ha'Melech only after destroying Beis ha'Ba'al (verse 18)?
1.
Malbim (18-19): First they fulfilled the first Bris, and afterwards the second.
2)
What are "ha'Kari veha'Ratzim"?
1.
Malbim (from Divrei ha'Yamim II, 23:20): They are the Adirim (officers) and rulers.
3)
What is "Derech Sha'ar ha'Ratzim Beis ha'Melech"?
1.
Rashi: It means El Beis ha'Melech.