Aha oke! I would go for the 5* players first (the youngest ones) and PT them to a 6* > 7* and perhaps to a 8* (depends how much your willing to spend). I would not recommend to PT the 4* and lower ones (useless and takes time).
I see that you have around +400T, how much of them are you willing to spend on green packs? (best deal > 50 packs:46T)
I burned almost 350 green packs on my 7 scouts (6* > 7*) and 2 youngsters (5* > 8*) last week. Took me 4- 5 days.