When Barcelona-born Astrid Motsenigos realized she couldn’t find the same “beautiful, everyday items” for her daughter locally that she could while traveling, she decided to open her own boutique. Now her South End store showcases a mix of wooden toys, nursery decor and European apparel, some of which are U.S. exclusives. CouCou also offers a quiz-based personal-styling service for kids, along with a playroom and classes such as Baby and Me yoga.