If you train C's the first guy won't fit in well. Also I think his many atrocious skills are too annoying so I'd rather sell him since 18 yr old hall of famers do make you nice money.
And they guy with star potential has a bit too low potential. You won't get much money for him. Maybe if you need to fill up a third spot he could slip in with your C's and you can train him up to a backup (don't know the player levels in div II in Japan).
But that's just my opinion. Maybe someone else would advice to keep a hall of famer 18 yr old draft because it doesn't happen that often that you draft one yourself.
Crunchy! If you eat fast enough