Bearing in mind that in Pasuk 4, the Torah mentioned the Choshen before the Eifod, why here, does it mention the Eifod first?
Oznayim la'Torah: Because, on the one hand, the Kedushah of the Choshen exceeded that of the Eifod, on the oher, it was not usable without the Eifod, since it was by means of the straps of the Eifod that it was attached to the Kohen Gadol's body.
How did they obtain the gold threads?
Rashi and Ramban (Sh'mos 39:3): They beat out flat sheets of gold and cut them into thin strips. 1
How were the multicolored threads for the Choshen and the Eifod made?
Rashi: They spun one golden thread with six threads of Techeiles wool, with six threads of purple wool, with six threads of scarlet wool (all spun), and with six threads of twined linen, 1 before spinning them altogether - so that each thread comprised twenty-eight threads.
As the Pasuk describes in Sh'mos 39:3 (Rashi).
Only the Kohen Gadol wore the Eifod, and it comprised gold, three colors of wool, and linen. Why were eighty-five Kohanim called "Nosei Eifod Bad" (Shmuel 1 22:18)? Moreover, "Bad" implies that it was made totally of linen?
Ramban (in Pasuk 30): Based on the two questions, it seems that Moshe handed over the details of the Urim ve'Tumim, together with the secrets of the Torah, to the Gedolei ha'Dor, and that eventually, David ha'Melech and the Kohanim of Nov made themselves a linen Eifod, similar to that of the Kohen Gadol - only it was made of linen. 1
Moshav Zekenim: Perhaps also Bigdei Kohen Hedyot are called 'Eifod' - which has connotations of an ornament.
Radak and Abarvenel #1 (Shmuel 1 22:18): Targum Yonason there writes 'eligible to wear a linen Eifod.' Great Ovdei Hashem wore it - such as Shmuel (1:2:18) and David (Shmuel 2 6:14). It was not one of the Bigdei Kehunah. 2
See Ramban, Ibid. DH 've'Efshar'.
Metzudas Tziyon (Shmuel 1 2:18): It slightly resembled the Kohen Gadol's Eifod.
This answer does not explain why it is called "Bad". (PF).
