Is it possible to minify ServiceWorker script output?
Yes, offline-plugin perfectly works with official webpack.optimize.UglifyJsPlugin, so if it's used your will get minified ServiceWorker script as well (no additional options required).
Is there a way to match assets with dynamic file names, like compilation hash or version?
Yes, it's possible with pattern matching, which is performed by minimatch library.
Example: main: ['index.html', 'scripts/main.*.js'].