Washington II has one year of eligibility remaining.
Penn State marks Sowell's fourth school in five years.
Carnell has three years of eligibility remaining.
Brookins was with the Cyclones for one season, but preserved his redshirt and did not see any game action.
Ebel becomes the third Iowa State linebacker to transfer to Penn State.
Jarod Crespo's hat trick earned a split for the Nittany Lions to start the second half of their season.