SAUGUS ? Four new tenants have moved into the Square One Mall during the past three weeks.Crazy 8, a children’s clothing store owned by Gymboree Corp., opened its doors on April 27, according to Susan Yee, general manager of the shopping mall on Route 1 south.Yogi’s Dog House, owned by Yogi Sood, was scheduled to open Monday.The Magic Castle, a gift shop carrying San Rio products and brand names such as Hello Kitty, is up and running. It is owned by Jenny Chang.The fourth enterprise, slated to open Thursday, marks an expansion for Lynn-based Pet Express.”This will be their third location,” said Laura Adams, a spokesman at Regan Communications, which represents Square One Mall’s parent company, Simon Malls.The original Pet Express is located on the Lynnway in Lynn. The second store is at the Liberty Tree Mall in Danvers. The latest Pet Express will take over the retail space once leased by Debby’s Petland.”It’s nice to see them growing,” said Yee. “They’ll open for business on May 19 and the grand-opening will be May 21. The puppies are coming in this week.”Yee said Pet Express owners and brothers Robert and John Mellace are passionate about pets. “The puppies are not just a business to them,” she said. “They can’t wait to open up.”Yogi’s Dog House will take over the space formerly occupied by Gourmet India. It is a specialty hotdog eatery serving menu items like the Fenway, the North End and the Piglets (Pigs in a Blanket, each with its own thematic toppings. The restaurant will also serve Italian sausages.Yee said the shopping mall is still searching for an anchor restaurant that would blend with the family-oriented customer base and replace the defunct Twitters Bar & Grill.Twitters still faces a hearing before the Board of Selectmen regarding its liquor license and changes made to the premises without town approval.Formerly known as the New England Shopping Center, the Square One Mall was built in 1994 for an estimated $100 million. It is anchored by Best Buy, Macy’s, Sears and Dick’s Sporting Goods.”We’re a good mix,” said Yee. “We have stores here that the other malls in the area don’t, like Best Buy, and we have some good-value stores for those customers looking for bargains, like Filene’s Basement.”