Maybin will be a stud but he is nowhere near ready. The only way the Marlins should have him in the opening day lineup is if there is absolutly no one else. If they do call him up, expect a .220 season with a lot of strikeouts and a lot of stolen bases. Miller is a maybe. If he developed a solid second pitch (slider or curve) in the off-season and cna throw it for strikes, then he could be an effective starter next year. His stuff is filthy and his fastball has so much movement it is basically two pitches by itself. He will get off to a hot start because NL hitters will be completly unfamiliar with the way he pitches.
DLC should be in the opening day roster assuming he developed a semblance of control in the off season.