Expect a whole lot of Legal this summer. Legal Sea Foods, with a 31-seat bar, opened at Logan Airport’s Terminal B Connector this week. Meanwhile, two Legal concepts are planned for the upcoming months. Also look for the romantically named Legal on the Mystic at Somerville’s Assembly Row (300 Grand Union Blvd.) this summer, as well as Charlestown’s Legal Oysteria (10 City Sq. at Chelsea St.), opening in June. It replaces Todd English’s troubled flagship, Olives, which shuttered last year. Executive chef Richard Vellante will repurpose English’s brick oven and rotisserie to execute a “coastal Italian seafood” menu, says a rep.