Federko, 33, who has played his 13-year career with the Blues, scored 1,073 points in 923 games. He said he was sorry to leave St. Louis but looked forward to going to Detroit.
"Jacques Demers is a very good coach," Federko said. "I had three of my very best years with the Blues when he was coaching, so I'm excited that I'm going to be back playing for him."
McKegney, 31, after scoring 40 for the Blues in 1987-88, had only 25 goals and 17 assists last season.
Red Wing General Manager Jimmy Devellano said he needed to find replacements for Bob Probert and Petr Klima, who are not expected to play next season.
Oates, 26, is coming off his best season. He had 16 goals and 62 assists for 78 points in 1988-89.
MacLean, 31, scored 36 goals and 35 assists for Detroit, but finished the season in Demers' doghouse.