Yes the Unaware-Swagger strategy is perfectly fine. The User after using swagger on the opponent can copy the +2 attack boost, but not the confusion with Psych Up.
However if the opponent has simple, the user will still only gain a +2 regardless os what happens since Psych up affects the original booster not modified. This is the opposite when a simple user copies a +2 attack from the opponent, as it goes up to +4
Hope I helped!