2. As stated in the prior post, Edge support is coming to the Universal Web Adapter. You'll need to re-interrogate your applications if they are switching to Edge from IE as it will require a new adapter. You can replace your controls in your current automations with the controls from the UWA rather than write every automation from scratch.
3. You will need to upgrade to the latest version of Studio/Runtime when Edge support is released in order to get that functionality.
As far as I know the target date is still mid-January. If you want to start your migration, you can interrogate your apps in Chrome to make sure they run natively and are not using Compatibility Mode as that support hasn't been announced yet.