Business is booming for New Jersey Assembly Speaker Craig Coughlin. An attorney by profession, Coughlin was a low-key state lawmaker with a solo law practice and a handful of municipal clients in the years before he ascended to the third most powerful position in the Statehouse in 2018. No less meteoric is the rise of the law firm he co-founded as he lined up for that leadership post. Established with a couple of well-known partners, Rainone Coughlin Minchello has seen explosive growth in the seven years since it opened its doors. Representing local governments across the state, the Woodbridge…