[Vuejs]-Is Ionic+Vue as frontend combinable with Umbraco as backend? (Webpack frustrations)

This sounds more like a vue issue than a Umbraco one. You should be able to do it. After a quick google there is a working project here:

https://github.com/ionic-team/ionic-vue-conference-app

Have you tried explicitly installing packages with version numbers that work, e.g.

npm install @ionic/vue@0.0.4