Veilleux projects to compete for Pitt's starting job, as Kedon Slovis transferred after the season.
Keys had originally been committed to North Carolina since August.
Hamilton missed the entire 2021 season with an ACL injury.
Robinson announced his decommitment from Northwestern while wearing a Penn State wristband.
Tickets will be available for public purchase on December 16, with prices starting at $59.50.
Over 40 Penn State Law faculty members signed a letter encouraging the university to keep the two law schools in separate locations.