Try this:

Find: ([A-Z]. [A-Z]. )([A-Z]{1}[a-z]{1,}-[A-Z]{1}[a-z]{1,})------(works for R. M. Johnson-Hulk – run first)
Replace: \2, \1

Find: ([A-Z]. )([A-Z]{1}[a-z]{1,}-[A-Z]{1}[a-z]{1,}) -----(worksfor M. Johnson-Hulk –run second)
Replace: \2, \1

Find: ([A-Z][. ]) ([A-Z][. ]) ([A-Z]{1}[a-z]{1,}) ----(Worksfor R. M. Johnson – run third)
Replace: \3, \1, \2

Find: ([A-Z]. )([A-Z]{1}[a-z]{1,}) -----(Works for J. Smith– run last)
Replace: \2, \1