> 1) Can I run jlink somewhere in the build process?

No need. Just specify your JVM requirements and the launcher will automatically use (or download if necessary) a compatible VM. This allows JVMs to be shared between apps, and your app updates are much smaller since they don't include the VM bundled directly.

> 2) Can I use a private npm repo like Verdaccio, or are there plans for other (non npm?) backends in the future?

Right now it's pegged to the public npm repo, but I'll be exploring other options soon, including private repos, self hosting, GitHub releases.