Rabbi Nachman wanted his students to go out and “discover” much like the sons of Esav want to walk on other planets, we need to make discoveries within Torah learning.
That being said, there is only one Rabbenu. Saba never said he was a talmid, as far as I can recall, except as a talmid of Rabbi Israel Karnoner…before having received the Petek which revealed to him his own signature. There is only ONE Rabbenu, you will have to think about this.
TOLDOT JACOV specifically refers to JOSEF or in the case of ISAAC, to ISAAC!!! Not quite Zera…even the toldot of Nahor don’t mention Lavan who finished his career a Rasha (only RIVKA is mentioned). Toldot has more to do with where a person ends up in life then where he begins. Is the big accomplishment of Isaac that he was from Abraham? This negates that others achieved this. On the other hand, the big accomplishment of Jacob is that he brought forth Josef.