Okay I suggest trying this method. Do b2 and press and hold f, then observe how Lee gets to mistep. While he is mistep press b and see if Lee gets back to neutral. You need to understand the timing, it takes practice but I am sure you will be able to learn it. Key is to understand the animation.
i recommend SSR b4 -> d3 as a combo ender rather than bb4 -> ff3. D3 is unscaled damage so it does more damage. Also if u ssr before, the opponent cant spring kick which is the only way they can counter b4 -> d3 ender
at 1:20 you show uf 4, > 4,u3 > b2 f N > b N WS 3, 4 > f4,1 > DASH > bb4, ff3 but what you actually do is uf4 > 4,u3 > b2 F, BN, 1,2 F, f 4,1 > DASH bb4, ff3
Keep at it, this video helped me quite a bit: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-aQck4MhpCBU.html Although I guess this one is mainly for doing while standing moves after Mist Step. The Mist Step>back sway cancel from back two is slightly different than just doing a Mist Step>back sway.