I don't doubt that Fuchsia will support Go, but Dart appears to already be Fuchsia's officially preferred userspace language (via Flutter).
Indeed. It seems preferred way for Fuchsia UI side. Go is more of infrastructure plumbing there. As someone who mainly work on backend stuff in enterprise apps I am happy with this situation.
What I am not happy with this whole browser platform embedded in frontend apps and called native and amazing. But that's for another discussion:-)
Dart is not a JVM Language. It can be compiled to the JavaScript or run in the Dart VM.
The wording was a bit confusing, but I think they meant "Java-like" and "VM-based" as separate things, not that Dart runs on the JVM.
Go is going to have better support on Fuchsia OS from Google.