The former Penn State wide receiver recorded 98 catches, 1,658 yards, and 13 touchdowns from 2017-19.
Clifford was Penn State's leader in wins as a starting quarterback, passing yards, total yards, and passing touchdowns.
Castro-Fields appeared in eight games for the Commanders last season.
Amos played for Penn State from 2011-14.
The former Penn State wideout was signed as an undrafted free agent in 2023.
Tickets to see the group live will go on sale at 10 a.m. on Thursday, August 29.