DockersMen's Edson Slip-On Loafer

Is this really leather? I’m asking because I bought a Dockers (Cayenne slip on) before that was advertised as leather but it wasn’t.

I bought these in March. The heals have holes already but the rest of the shoe is still like new. Are they under a warranty?

What is the difference between 10 d (m) us size and 10 e us size? which one is wider?

Is there any metal used in the construction of this shoe? Metal shank or nonmetal? I travel thru security checks a lot and need a show without metal.