- Vulkan support is present in all mainline drivers for like a year now, nvidia doesn’t just drop support for cool new features. That said, vulkan spec is evolving and nvidia keeps updating their implementation to latest standard of vulkan as needed.
3a) Practically no (technically wayland is merely a protocol that gets implemented by wayland compositor).
3b) Nvidia doesn’t comment on future releases. They already proposed a EGL-stream based implementation which got shut down by most wayland compositors. There are many moving parts in attempting to upstream nvidias idea and at various points in time several patches were proposed to upstream projects.
To best of my knowledge the answer is “not yet” and “it’s complicated”.