I think it was the actors themselves. I say this because: (1) the credits do not indicate otherwise, and (2) I read that the actor who plays Eddie originally tried out for one of the other roles, but was selected to portray Eddie because of his great falsetto voice.
Smokey Robinson sang a song at Blue's funeral on the Temptations movie.
Leon Robinson
Archived recordings from David Ruffin were used for his character's vocals in the miniseries. Most notably was when "My Girl" was being sung. However, Leon provided his own vocals during some songs, "(I Know) I'm Losin' You" and "Ain't Too Proud to Beg" in the miniseries.
Smokey Robinson.
Melvin Franklin
Smokey Robinson sang a song at Blue's funeral on the Temptations movie.
Leon Robinson
Archived recordings from David Ruffin were used for his character's vocals in the miniseries. Most notably was when "My Girl" was being sung. However, Leon provided his own vocals during some songs, "(I Know) I'm Losin' You" and "Ain't Too Proud to Beg" in the miniseries.
Marti Frederiksen
The Temptations sang Get Ready.
Smokey Robinson.
Melvin Franklin
The Temptations.....
Temptations
The song is "Stay" by: The Four Seasons
the temptations
Rare Earth