One point I'd change and that's if you want to train a SA or EXTRA ROLE then do that first so the player can still train quickly. Once he goes up a * then it takes longer and more green packs to train the SA in.
I said so because we all know that SA are not so great so its better to train your player to a level where he can play well i.e 5 star then start training a SA...
And why you will buy a 4 star player to train if you can get a 5 star......