the third act of Wonder Woman was completely reshoot and they even changed Ares design
Where the fuck did this rumor even come from. I can argue if you're talking about the rumor about No Man's Land (which got debunked by Patty anyway) but literally no one mention anything about this.
Aquaman had Black Manta forced in there because Geoff Johns demanded that he be in the movie even when Wan wanted to focus strickly on the Atlantean stuff
Manta had an entire fight sequence to himself, a full costume and plenty of concept arts. How are you making the assumption that James Wan doesn't want him there to begin with.
they hired the John Wick guy to direct Birds of Prey reshoots
His stunt company is working on Birds of Prey to begin with. I won't even comment on whatever that reshoot is since every trades are reporting it as a reshoot for action