In Zack Snyder's Justice League, Mera is an orphan. ("My parents died in the wars. [Atlanna] took me in.") In Aquaman, her father is a major player in the narrative.Re: Snyder and Justice League, I've yet to see anybody using the theatrical cut of the film as an example of WB's 'course correction' explain why none of the films that followed it deviated from the overall general tone and aesthetic established by MoS and BvS, or why WB never demanded that Aquaman and The Flash be revised so that they were narratively compatible with the theatrical cut of JL.
I don't recall Aquaman contradicting anything from the theatrical JL.
And the assertion that the wildly colorful, cheerfully goofy Aquaman shares anything with the "tone and aesthetic" of Snyder's DCEU films is certainly ... a perception.