1)
Was Ish Boshes king for only two years? He was king after Sha'ul died, and after Ish Boshes died, David was king over all of Yisrael. David was king just over Yehudah for seven years (verse 11)!
1.
Radak (11): For five years, David was king over Yehudah, and there was no king over the rest of Yisrael.
2.
Metzudas David: For five years, Ish Boshes increased the places of which he was king. After this, for two years he was king over all of Yisrael except for Yehudah.
3.
Malbim: For two years he was king over all of Yisrael except for Yehudah. He was king another five years, but during the that time much of Yisrael went to follow David, like it says in Divrei ha'Yamim I, 12:23,24.
