Our colleagues from Google significantly reduced platform merging cycles over the past 2 years. Now it takes approx. few months. And they work a lot on adapting Android Studio features to K2 (as code analysis engine).
Android IDE plugin for IntelliJ IDEA is build from Android Studio. So yes, we will wait Android Studio to be ready first.
I, working for JetBrains, cannot comment or reveal dates and plans of my colleagues from Google. But I’m sure they tell about them soon.
AGP doesn’t relate to K2-IDE Mode.