Plot hole: After Manny has agreed to go with Ellie, Crash and Eddie, he says "Ellie can be the mommy." He said Ellie's name, but she had never told him, nor could he have heard it when Eddie was talking to her. (00:22:45)
Suggested correction: Manny would definitely have been able to overhear Eddie calling out Ellie's name. As Ellie went to have a word with the possums, it's not like they went somewhere else, they just turned away. And Eddie wasn't precisely quiet.
Manny was also having a discussion with Sid and Diego so he wasn't paying attention to the conversation where Eddie said her name.
You don't necessarily have to be paying direct attention to a conversation to be able to pick out words.
I agree. Even if Manny wasn't paying attention, he still could've heard Eddie saying Ellie's name.