1)
When did Kalev dispossess them?
1.
Rashi: It was after Yehoshua died, like it says in Shoftim (1:20). It was written here only due to the division.
2.
Malbim: He dispossessed them now, in Yehoshua's lifetime. Malbim (Shoftim 1:10) - here it is attributed to Kalev; he was the head of Yehudah, and they followed him. It is repeated in Shoftim along with everything that Yehudah conquered.