I think you start with G-Leaguers already in the system who you know can do some stuff. Celts have already done that with Hauser (can shoot) and Kornet (can play basic interior defense).
Unless a vet who has actually played at a decent level this season becomes available for the minimum, I would fill out the remaining spots with the best G-League players available. I don't know enough about the G-League to have an opinion on which guys would fit that description.