MrFuton said:
I am really new in the sakuga so I have a basic question. Is the heavy video reference a fair method in the sakuga? I read that realistic scenes of some animators like Okiura are product of copy frame per frame real scenes. Is it real? Can anyone anyone tell me the true?
It depends. Disney uses references all the time. And I wouldn't be surprised if Japanese animators did the same once and a while (obviously not as often due to smaller timescales).

I'd say it depends on animator, though I don't know how many animators in Japan do.