Snapper Carr mentions heads of state from over 400 countries attending Superman's funeral; even with "in-universe" countries such as Kaznia and Atlantis, the actual number does not even reach 200.
During J'onn's eulogy a large shrub is visible over Hawkgirl's shoulder in the shot in front of her, but in the next, closer shot, it cannot be seen where it was.
When he bears the coffin with the other members of the League, Green Lantern alternates between wearing the robe he was first shown in and nothing over his uniform.
From above, the paths in the grass in front of Superman's memorial form his "S" insignia; however, the view of Batman addressing it shows a straight-line path behind him, inconsistent with that configuration.
When Wonder Woman is dressing for the funeral and putting her white robe on, not only does she not lift her hair to put the robe on and around her neck, but the robe magically goes from being on top of her hair to underneath it.