Tom Welling actually played SuperBOY, not Superman, in "Smallville", and even stated in the "Crisis on Infinite Earths" cross-over that he gave up his powers, (much like Christopher Reeves in "Superman 2), in order to concentrate on raising a family with Lois.
None of the actual "CW-ers" appear in this film either: Melissa Benoist (Supergirl), Tyler Hoechlin (Superman), Brandon Routh (Superman), and Grant Gustin (The Flash).