The Nittany Lions are set to be joined by Clemson, San Francisco, and Fordham.
Wings President Greg Bibb said Owusu applied for another year of NCAA eligibilty.
Niederhauser was the Nittany Lions' first portal commit from the current cycle.
Owusu was the first Lady Lion drafted since Maggie Lucas in 2014.
Lambert-Smith was absent from the Nittany Lions' Blue-White Game despite being listed on the roster.
The shirt went on sale on Sunday, April 14.