I need the functionality of being able to catch events (such as tap on a particular point inside the 3D object) and trigger actions (such as showing / hiding labels corresponding to the tapped point). Is this functionality currently available for Wikitude SDK for Ionic / JS / Android Native?
Also, is the SDK able to read the layer / vertex names that model comes with from an external source (such as Sketchfab)?
Yes you can e.g. check the '3D model - Interactivity' sample in our JS or Cordova sample app. This shows how you can interact with an animated 3D model.
The SDK doesn't support accessing vertices directly.