Here is a guide for all clothing in the mall which will unlock 2 achievements. You must progress through the storyline to at least case 2-3 for all access to the mall.
Youtube user awyeagameboy has done a nice job making a video going through the mall and changing into all clothing without wasting time putting on the same clothing.
Al Fresco Plaza/Wonderland plaza (at 1:32):
You will also obtain this achievement in the process if you do all clothing in the videos: