question for the fashionistas

[wurm]

I'm going to my niece's wedding in NY Friday (leaving tomorrow). My usual daily wear is jeans and a tee-shirt or sport shirt. For the wedding I'm planning on grey slacks and a white or blue shirt and tie.

1. Is a blue blazer with brass buttons still considered timeless? If not, I'll skip the jacket altogether.
2. Shoes: black or cordovan?

Thanks.