Which pegs and cords did the Bnei Merari carry?
Rashi: They carried the pegs and cords of the pillars of the Chatzer 1
Rashi: They were placed on top of the pillars in order to attach the hangings to them. According to the Ramban, the pillars did not have pegs. See the Beraisa that he cites.
Rashi: They were used to attach the hangings to the ground, to prevent the hangings from flapping in the wind.
Ramban: Since the "v'Es Meisreihem ve'Es Kol K'lei Avodasam" (in Pasuk 26) refers to the hangings of the Mishkan and the Ohel Mo'ed that are mentioned in Pasuk 25, but not to the Chatzer. See Ramban DH 've'Lo Matzasi'.
See Ramban DH 'Aval'.
Why is there an extra 'Lamed' in "l'Chol Keleihem"?
Rashi: Refer to Shemos, 14:28:1:1*.
What are the connotations of the phrase "uv'Shemos Tifkedu Es Klei Mishmeres Masa'am"?
Ramban and Seforno (on Pasuk 49): It means that Aharon and his sons should designate each ben Merari by name, and instruct him exactly what he had to carry. 1
Ramban: 'Ploni should carry so many planks, and Ploni, so many bolts or pillars', And it mentions this specifically by the Bnei Merari, because, since they carried the heavy things, they were the most likely to try and lighten their load and push off whatever they could on to their friends. But in fact, by the same token, the Bnei Kehas returned the Kelim to Elitzafan ben Uziel and the Bnei Gershon, to Elyasaf ben La'el. However this appears to contradict what the Ramban himself wrote in above. Refer to 4:16:2:1**, 4:49:1:2*.