>>2261660Most of the images that OP posted are cropped so that the whole body isn't in view. That's bad for a reference.
The images are meant to be looked at, but are poor for referencing unless you are cropping the pose the same way that the photographer does (which is not a good way to draw).
As far as character design, the characters they're cosplaying are already established. Copying another artists character design is pretty lazy. That includes artistic changes that cosplayers make to their costumes.