Re: Marconcini. He missed his 2012 season. As such, he had only used 3 years of eligibility. So this works the same way that basketball does: he is a grad transfer with one year of eligibility left.
You're thinking of the Greg Paulus example, where he exhausted all four years of basketball eligibility and then transferred to Syracuse to play a year of football. That's a different scenario because Paulus had already used all 4 years of basketball eligibility. If I'm not mistaken, Paulus could have played for Duke football had he wanted to do so, but apparently didn't have the opportunity for playing time.