USING A KLI SHARES FOR THE WATER
Question: Why do we fill up a utensil which is not a Kli Shares before Shabbos?
Answer (Ze'iri): Our Tana adopts two positions which would cause the water to become Kadosh in the Kli and subsequently be Pasul through Lina on Shabbos night.
There is no upper limit to the amount of water used for the Nisuch (hence the Kli Shares would be Mekadesh since the greater amount of water is still the "proper" amount for the Kli Shares).
The Kli Shares is Mekadesh even unintentionally.
Chizkiyah subscribes to the first position but says that the second position cannot be derived from our Mishnah.
It is possible that the Kli Shares may not be Mekadesh unintentionally.
However, we could not use a Kli Shares owing to a Gezeirah lest these waters be confused with waters which were put in the Kli Shares intentionally.
R. Yanai citing R. Zeira explains how the Mishnah could reject both the first and second position (ie. there is an upper limit to the amount of water, and that a Kli Shares is Mekadesh even unintentionally) and still prohibit this water lest people think it was drawn for Kidush Yadayim (which could be any amount).
Question: Why is exposed water Pasul for Nisuch given that it can be filtered from any venom!?
Answer: Our Mishnah presumably rejects the position of R. Nechemyah.
He holds that we may rely on filtering to permit exposed wine.
Answer: Even according to R. Nechemyah, this wine/water is Pasul for Nisuch owing to the stricter standard regarding bringing water to the Mizbe'ach than permitting such wine to a person.
THE CHALIL OF THE BEIS HA'SHO'EVAH
(Mishnah): The Chalil could be played for five or six days of Sukos.
This refers to the Chalil of Simchas Beis ha'Sho'evah which does not override Shabbos or Yom Tov.
(Gemara): The text in some versions of the Mishnah was Beis "ha'Sho'evah"; in others it was Beis "ha'Chashuvah"
(Mar Zutra): There is a basis for either word, Sho'evah and Chashuvah, to appear in our Mishnah.
Sho'evah derives from the Pasuk u'She'avtem.
Chashuvah derives from the fact that the Shitin are very important, originating in Creation.
CHALIL ON SHABBOS AND YOM TOV
(R. Yosi b. Yehudah): Chalil overrides Shabbos.
(Chachamim): It does not even override Yom Tov.
(R. Yosef): The above Machlokes revolves around whether Shir is primarily with a Kli (the playing is Avodah) or primarily with one's mouth (the playing is not Avodah, and does not override).
All would agree that Simchas Beis ha'Sho'evah is not Avodah, hence our Mishnah (that the Chalil does not override Shabbos or Yom Tov).
R. YOSEF'S SOURCE FOR THE ARGUMENT BETWEEN R. YOSI AND CHACHAMIM
We find that Rebbi and R. Yosi b. Yehudah argue over the Kashrus of a wooden Kli Shares.
Their argument seems to revolve around whether or not we infer from the wooden Chalil of Moshe Rabeinu to permit wooden Kelei Shares.
This would seem to be based on whether Shir is primarily with a Kli (in which case we would learn from Moshe's Chalil) or by mouth (and the Chalil is not Avodah).
No, they could both hold that Shir is with a Kli and argue over whether we may apply a fixed source (Moshe's Chalil needed to be wood) to an unrestricted application (other Kelei Shares).
Alternately, they could both hold that Shir is with the mouth and that we do not learn from a fixed source and still argue whether Menorah informs other Kelim through Kelal u'Frat or Rov u'Miut.
Rebbi would learn Kelal u'Frat U'chlal (and all Kelim must be metal, akin to the Menorah).
R. Yosi would learn Rov u'Miut u'Rov (and Kelim may be made of any material except Cheres).