A former vice president of the National Basketball Players Association was arrested Wednesday and added to a criminal case in which 18 former NBA players were charged with illegally pocketing millions of dollars by defrauding the league’s health and welfare benefit plan. The rewritten indictment added Keyon Dooling to the case first brought in October, when federal officials said a number of former NBA players combined to collect about $2.5 million from the benefit plan.