Suggestions by @keiranbatkin2

Matt Lanter

as Batman in Superman

Score: +1

Camila Mendes

as Zatanna in Superman

Score: +1

Chandler Riggs

as Jimmy Olsen in Superman

Score: +1

Kiernan Shipka

as Supergirl in Superman

Score: +1

Martin Wallström

as Lex Luthor in Superman

Score: +1

Carrie Coon

as Mercy Graves in Superman

Score: +1

Felicity Jones

as Lois Lane in Superman

Score: +1

Candice King

as Black Cannery in Superman

Score: +1

Charlie Hunnam

as Green Arrow in Superman

Score: +1

Landon Gordon

as Impulse in Supergirl

Score: +1

Jacob Elordi

as Mon-El in Supergirl

Score: +1

Noah Centineo

as Lightning Lord in Supergirl

Score: +1

Rowan Blanchard

as Saturn Girl in Supergirl

Score: +1

Louis Partridge

as Cosmic Boy in Supergirl

Score: +1

Zachary Gordon

as Lighting Lad in Supergirl

Score: +1

Jace Norman

as Braniac 5 in Supergirl

Score: -1

Jeremy Ray Taylor

as Bouncing Boy in Supergirl

Score: +1

Kiernan Shipka

as Supergirl in Supergirl

Score: +1

Mark Hamill

as Henry Allen in The Flash

Score: +1

Elisabeth Shue

as Lorraine Fries in Fries

Score: +1