1)
What is the meaning of "l'Re'ehu"?
1.
Rashi: It is to his beloved. This is like l'Re'av. Also "Magen Giboreihu" (Nachum 2:4) is like Giborav, and "b'Hispalelo b'Ad Re'ehu" (Iyov 42:10) is like Re'av.
2)
Why did David not send from the spoils before this?
1.
Rashi: Since Amalek despoiled Negev Yehudah and Negev Kalev, David wanted to return the theft. Along with this, he sent a Brachah to all the places, to recall the miracle.
