Ellies was the second Nittany Lion to announce his return to the team after tight end Tyler Warren.
Cephas had 22 receptions for 246 yards during his lone season with the Nittany Lions.
Fleming was the No. 6 wide receiver and No. 32 player overall from the transfer portal.
The Nittany Lions will travel to Bucknell on Tuesday, February 13, to begin the season.
Jeff Tambroni and Co. will host Colgate at noon on Saturday, February 3, at Panzer Stadium, to open the season.
Oliver appeared in 14 games for the Deamon Deacons in 2023.