But is Rust merely a new face on Ada?

They share some features. But what language does not share any features with any other language? Any new language these days will be heavily inspired by and take features from other languages while making changes to or pulling in features from other places to create a mix that is unique to that new language. Rust is far more than just its GCless memory safety features and I am not even sure if they are inspired by ada or were just arrived at a similar solution to ada - they are not exactly a one to one matching with how ada does anything. If anything I believe that rust is much more heavily inspired by ocaml than ada.