1)
The verse mentions the bad figs, but does not teach anything new about them!
1.
Radak: It is as if it says 'those who remain [in Eretz Yisrael] will be [like] the bad figs.
2.
Malbim: In verse 3, Yirmeyah himself said that the bad figs cannot be eaten. Hashem informed him that He put those words in Yirmeyah's mouth; it was a Nevu'ah.
2)
Who dwelled in Egypt?
1.
Radak: It is those who will go with Yochanan ben Korach.