Good overview; a couple nitpicks:

Technically Scala's inference is not Hindley-Milner since you still have to declare method argument types for JVM interop.

The speed difference between Scala and Clojure has less to do with the static/dynamic gap than the fact that Clojure relies upon reflection by default. However, once you identify your bottlenecks, adding type hints to remove reflection is pretty easy.

Good stuff.