First off, I LOVE the pigtails! I have it on both of my files, and I couldn't be happier. :7: It's really a dream come true to be able to style your character as you see fit in a Pokemon game. Even if the options are somewhat limited, I really like what they do have. It would be cool if you could take off your hat though.
After some research I was able to figure out how to get into the boutique as well as unlock the hairstyles. There is a hidden "style" stat that increases as you complete activities within the city. Doing a variety of the above mentioned things isn't necessary, as I was able to unlock both the boutique and hairstyles during my first visit to Lumiouse after obtaining the first badge. By making PR videos and doing the one star restaurant several times (good money too!), I managed to get my style up. I just kept doing the restaurant twice, then going to the boutique and salon to check if anything changed I was able to get into the boutique first, but it was very soon after that the salon had more hairstyles.