Cooper's move comes more than two months after he left the Nittany Lions.
The Nittany Lions bumped up three spots from their No. 13 rank in the 2022 end-of-season poll.
Fetrow joins the Dragons after coaching stints at Penn State, West Chester, and Villanova.
Mike Gambino picked up four pitchers, including a transfer from Southern New Hampshire and three Class of 2024 recruits.
The 6'2," Rochester, New York, native will be the Nittany Lions' third commitment of the Class of 2025 alongside recruits Marin Collins and Lexi Gin.
Mizrahi comes to Penn State with two years of eligibility remaining after spending time in JUCO ball.