Hey guys, I have created a starter repo for using the Kotlin React wrapper with a custom Webpack setup for Kotlin 1.3 JS multiplatform projects. This starter is setup with JS/JVM multiplatform but it will work for any multiplatform combination you would like to do. I have put comments in the webpack config files and some of build.gradle to explain the configurations. It starts you off with a working React component and multiplatform sample files. I hope this helps everyone with their Kotlin/JS 1.3 multiplatform projects.
https://github.com/gbaldeck/react-js-jvm-kotlin-multiplatform