to give a DMC/MC and MC/AMC those extra positions, needs about 50 greens.
To make them stronger (middle 6* players), needs another 50.
(if they are fast trainers).
If you have another 50 greens to give them sa, playmaker is ok with the DMC/MC and shadow striker better for MC/AMC.
If you haven't any descent F-C or C-K specialist, you can also give this one too (but better test him in few games first, if he has the talent).