Njie turned into an integral part of the Nittany Lions' starting lineup and earned 26 starts through 37 appearances in his freshman season.
The three candidates respectively received 12,141, 11,745, and 10,281 votes from fellow alumni.
The full renovation, which would last around four years and cost an estimated $700 million, will include maintenance projects, winterizing, and architectural and design development.
As a freshman, Mahaffey averaged 9.4 minutes, 2.8 points, and 1.7 rebounds per game, while shooting at a 56.9% clip from the field.
Booth, the son of Penn State hoops legend Calvin Booth, boasted a four-star status as a recruit and will take his talents to South Bend.
Bouquot will arrive in Happy Valley with one year of eligibility remaining.