Not sure how you define "first class" but:

Do you support WhatsApp, Messenger and Signal?

Yes we do! These also work with push notifications via MicroG or Google Play Services to ensure you get instant updates!

Do you support X app?

In general, we support almost all apps that work on Android, only really having difficulty with banking apps or digital id apps (due to Google Play Integrity Check). We ship with either Aurora store or Google Play Store to have full access to the apps on the Google Play Store