Some employees from the billionaire’s firm, Point72 Asset Management, are moonlighting in crucial roles for his baseball team. Many are tasked with improving data analysis and technology. In the 18 months since billionaire hedge-fund manager Steve Cohen bought the New York Mets, the baseball world has wondered how the sport’s wealthiest owner would use his vast resources and financial acumen to fix a historically hapless organization. The answer was both simple and revolutionary: He brought his hedge fund to the Mets—literally.