The issue many will note here is that you've focused on two blucher (also known as derby) models. See how the eyelets are on a flap? That is considered more informal. Balmoral models (Park Avenue, Fifth Avenue, Strand, etc.) are more formal and are traditionally worn with suits.That said, I wear black Clifton periodically with my suits (I wear a suit daily). It's not my favorite look, but it's totally pass-able. So I would go with black Cliftons and brown Delrays.