Why the OP format works for this
A series opening is a very constrained piece of filmmaking: a few seconds, no dialogue, and a job to do — establish a character and a mood fast. That constraint is exactly what makes it a good template. There is no plot to sustain, so the model only has to hold your likeness and the palette steady while the choreography carries the energy.
Source photos that hold up
Cel shading throws away most of the tonal information in a photograph and rebuilds the face from a handful of flat regions, which means the structure it keeps is bone and hair, not skin detail. Front-facing and evenly lit gives it the most reliable structure to work from. Sunglasses, heavy fringe and strong side shadow all remove the cues it needs, and the character drifts off-model as the fight moves.