In the orderly books from the Rhode Island Campaign in 1778, there are orders from General Sullivan forming a light corps which I have never seen any one mention in light infantry compendiums. These books can be identified on our orderly book website: http://www.revwar75.com/ob/ob1778.htm
General Sullivan also had a Light Corps on his Expedition against the Indians in 1779. There is an orderly book online from which some detail can be gleaned: http://www.rootsweb.com/~usgenweb/pa/1pa/1picts/proctor/pf5.html . It was commanded by BG Hand, and that is the best way of searching for entries in the OB, use the find on this page command from your browser and search for Hand.
We also list a couple light infantry orderly books on the Continental Orderly Book Index.
Can't answer your question on whether the RI Regiments had lights.
To Join the Company of Military Historians click here