WHEN ARE ANIMALS CONSIDERED SPECIFIED?
Counter-question (Rav Papa - Mishnah - R. Shimon ben Gamliel): If a man designated three animals for his Nezirus, and did not specify which is for which Korban, the one Kosher for the Chatas is (offered) for the Chatas, the one Kosher for the Olah (the yearling) is for the Olah, and the one Kosher for the Shelamim (the second year ram) is for the Shelamim.
This shows that animals are considered specified!
Answer (Rav Simi bar Ashi): Regarding a Ken, it says "he will take" and "he will offer." This teaches that a Ken is specified only when it is bought, or when the Kohen offers it;
Regarding Korbanos Nazir, you cannot say that the Chatas will be offered for the Olah. The Chatas is a female, and the Olah is a male!
Question (Rav Hamnuna): A Ba'al Mum is not like Stam money!
(Mishnah): When can a Nazir bring the Korbanos of his father? Levi was a Nazir (the Meforshim prefer this text). He separated money for his Nezirus, and died. His son said 'I am a Nazir on condition that I bring the Korbanos of my father.'
(When the son does not bring his father's Korbanos.) Stam money goes to Nedavah;
If he had a specified animal:
If it was a Chatas, we leave it to die. An Olah is (offered) for an Olah, and a Shelamim is (offered) for a Shelamim.
Suggestion: This applies even if the animal had a Mum! (We redeem a Ba'al Mum Olah or Shelamim, and use the money for a similar Korban.)
Answer: No, it refers to a Tam.
Question: If a Ba'al Mum is like Stam money, the Mishnah should say that a Ba'al Mum goes to Nedavah (and all the more so, Stam money)!
Answer: The Kedushah of a Ba'al Mum is its value (it is destined to be redeemed). The Mishnah teaches about money, and this includes a Ba'al Mum.
CAN A SON BRING HIS FATHER'S KORBAN?
Question (Rava - Beraisa): "His Korban" teaches that one is Yotzei with his own Korban, but not with his father's Korban;
Suggestion: Perhaps he is not Yotzei for a severe sin with a Korban that the father separated for a light sin, or vice-versa, but he is Yotzei for a sin of the same severity!
Rejection: "His Korban" - one is Yotzei with his own Korban, but not with his father's.
Suggestion: Perhaps he is not Yotzei with an animal his father separated, even for sins of the same severity, just like a Nazir cannot bring animals that his father separated for the father's Nezirus;
However, he is Yotzei (if he buys an animal) with money that the father separated, even for sins of different severity, just like a Nazir is Yotzei with Stam money of his father, but not with specified money!
Rejection: "His Korban" one is Yotzei with his own Korban, but not with his father's. (The Gemara brings the rest of the Beraisa before explaining Rava's question.)