The trouble between google and oracle wasn't about Java, it was about the Java Standard Library and Harmony. Which wouldn't really be solved by Kotlin.
Because they aren't metrics, but search integration. So as I understand it, they equivalent to google instant (safari literally; spotlight on the same vein) and they claim not to retain data on them.
To the best of my knowledge the only telemetry that OSX provides is crash logs, and only if you opt into it. You could argue that spotlight's (and Safari's) web search should be included, but I disagree.
For Swift, a lot of the designs were due to the ability to automatically transform Objective-C apis into swift APIs. The big issue from what i can tell is in extracting the first parameters name from the method name automatically.
What exactly are extension expressions, do you mean extension methods? If so, Swift does support them. I actually miss interface extensions in Kotlin, but thats a java cross compatibility issue.