The only way I can see the trunks working, is of they're more boxer trunks. More textured rather than just being red underwear. The way luisbajocollados tends to draw Superman would be the best way to do it, like this piece here.

I mean this movie is a HOMAGE to Superman is it not? That would be a neat idea as Supes first costume before he gets an upgraded look throughout the movie

lol No