I think this outfit was in DOA: Dimensions. It is lovely though <3.
I don't think sidestepping during stuns would be a good idea. I have enough trouble trying to set up Critical Bursts without always getting my strings counter held. Allowing the victim to sidestep just makes the situation worse for the aggressor who has to focus on applying the right mix-ups to achieve a CB or launch. Don't guess during stuns, read your opponent instead. I.E., which strings do they do at specific ranges? How do they react to pressure strings? What moves does the opponent use to achieve CB? Do they try to bait holds or throws? Etc., etc.
Also, sidestepping is designed to be used in anticipation of a linear non-tracking attack.