Lawyers for a senior executive for Chinese communications giant Huawei Technologies attacked the case against her as “fatally flawed” and full of “shifting theories” during an extradition hearing Friday. Canada arrested Meng Wanzhou the daughter of Huawei’s founder and the company’s chief financial officer, at Vancouver’s airport in late 2018. The U.S. wants her extradited to face fraud charges. Her arrest infuriated Beijing, which sees her case as a political move designed to prevent China’s rise. The U.S. accuses Huawei of using a Hong Kong shell company called Skycom to sell equipment to Iran in violation of U.S. sanctions. It...