The right panel
Note that Japanese is a context-driven language. Indeed Zoro's words なにもなかった "Nani mo nakatta (Notice that it's actually not なかつた "nakatsuta". "Tsu" is a small one here.)" means "Nothing happened" because it's his answer to Sanji's question ここで何があった? "What did happen here?" in the manga. However it can also mean "There was nothing./Nothing existed." in other contexts. If the sentence is used with the picture, people who know the manga would understand the meaning correctly, though.
The middle panel
Correction
Arigatō Zangetsu. Anta (not anata) wa ore da.
Both anata and anta mean "you", but anata is more formal and respectful. It doesn't fit with the protagonist Ichigo's character and the relation between him and Zangetsu.
The left panel
Your translation is correct. The Japanese sentence is お前達とは相容れない道にいる "Omaetachi to wa aiirenai michi ni iru."