Alternate Answer #2: They both do not have an apartment within; speaks of Kerachim (not subject to the laws of Nega'im), and one of Kefarim (subject to those laws).

Question: But the Beraisa implies (in the opinion of R. Yehudah) that synagogues are subject to Tum'as Nega'im (even if they are of K'rachim)?!

Answer: R. Yehudah meant all sanctified places.

Question: What is the Machlokes Tana Kama and R. Yehudah?

Answer: Over whether (R. Yehudah) or not (Tana Kama) Yerushalayim was apportioned to Shevatim.

This parallels an earlier Machlokes Tanaim.

The first Beraisa speaks of the parts of the Mikdash occupying the land of Binyamin and Yehudah, and of the Pious Binyamin yearning to contribute the land under the Mizbe'ach (and being compensated with the Aron).

The second Beraisa speaks of Yerushalayim as belonging to the entire people, and the resultant prohibition on charging for hospitality there (and the obligations which Chazal placed on visitors, in return).

Question: But a Beraisa limits the laws of Nega'im to homes which have highly specified ownership!?

Answer: Rather, we should use the first answers.

Question: How can we do the Chinuch for the substitute if the Pesul occurs after the Tamid Shel Shachar has already been brought by the first (no special Begadim to put on)?!

Answer: The Avnet.

Question: But what of the opinion that the Avnet which is worn by the Kohen Gadol on Yom ha'Kipurim is identical to that worn year-round by the regular Kohanim?

Answer (Abaye): He puts on all 8 Begadim and turns the flesh on the fire (an act prohibited to a Zar).

Answer (R. Papa): Doing the Avodah is [sufficient] Chinuch (as in the Beraisa regarding Keilim after Moshe's time).

There is a Machlokes Rebbi and R. Elazar b'R. Shimon whether the Avnet was Kilayim or only Pishtan.

We attempt to adduce that Rebbi holds it is Kilayim.

The Beraisa, which must speak on Yom ha'Kipurim, cites the Avnet as the only difference between the garments of the Kohen Gadol and of a regular Kohen.

No, the Beraisa could be speaking year-round and is only drawing contrasts between like-garments of the Kohen Gadol and the regular Kohen.

Ravin taught that the Machlokes was if the Avnet of the regular Kohen was Kilayim (Rebbi) or Pishtan (R. Elazar).

There was no Machlokes regarding the Avnet of the Kohen Gadol.

The Avnet of the Kohen Gadol on Yom ha'Kipurim was surely Pishtan, and during the year it was Kilayim.

R. Nachman b. Yitzhok cited a supporting Beraisa wherein Rebbi teaches that the Avnet of the Kohen Gadol on Yom ha'Kipurim is unlike the Avnet of the regular Kohen.

The Beraisa revolves around the word "Yilbash".

R. Yehudah and R. Dosa argue over its interpretation.

Rebbi gives two refutations to R. Dosa (our reason and a S'vara that an object of higher Kedushah should not be used for lesser).

"Yilbash" (according to Rebbi) would then teach that the garments need not be brand new.

R. Dosa is consistent with his opinion that the Begadim of a Kohen Gadol need not be placed in Genizah, but may only not be used for another Yom ha'Kipurim.

(R. Meir): Both Kohanim are treated as Kohanim Gedolim.

(R. Yosi): The first is restored to his post, and the second cannot function as Kohen Gadol nor as a regular Kohen (citing an incident in support of his view).

He cannot be a co-Kohen Gadol for fear of enmity.

He cannot be a regular Kohen out of respect for his elevated status.

(Rabah bar bar Chanah citing R. Yochanan): The Halachah follows R. Yosi.

R. Yosi also holds that if he does function as a Kohen Gadol, his Avodah is Kesheirah.

Here, too, in the name of Rav, the Halachah follows R. Yosi.