New signings Arnau Puigmal and Largie Ramazani are named.
Three 15-year-olds are in Man Utd's squad for the tournament.
The young Reds were beaten in the 3rd-place play-off by Club Brugge.
Both Barlow and O'Connor played in their country's final group game, and will face each other in the U17 European Championships quarter-finals.
Three minutes after coming as a sub, Aidan Barlow netted on his England U17 debut.