1)
Who are Dedan and Teima?
1.
Malbim: They are from Bnei Yishmael and Bnei Keturah (Bereishis 25:3, 15).
2)
What are "Ketutzei Pe'ah"?
1.
Rashi: They are cast off at the end of that direction.
2.
Radak: They dwell at the end of the world, in its corner. Pe'ah is the end of a matter.
3.
Malbim: They are the rest of Bnei Yishmael and Bnei Keturah, who cut off the ends of their Orlah (do Bris Milah).