Google apps dont have access to users account & training options

Hi there HKP 

For training you can take a look at the Android Enterprise academy, androidenterprise.training

You may also benefit from the AE docs - support.google.com/work/android

And if you'd like further reading, I also offer hundreds of articles on my site - bayton.org/android

To your questions - 

For fully managed devices, you'll need to start from a factory-reset state. When you configure fully managed user devices (I assume?) you'll be provided a QR code by Intune to scan. You can tap 6x on the welcome screen of all modern android devices to initiate the QR reader, and that should kick off the process.

For Google, you'll need to allow users to add their Google accounts on the devices. By default Intune will provision a generic managed Google Play account that is not associated with the user directly. If you're a Google Workspace customer with advanced Android management, you'll have further options that may save you on intune licenses too.

Hopefully that gets you started?

There isn't a wallpaper API accessible to Intune. I don't have a console available to verify but I should think this is more directed at the Microsoft Managed Launcher than generic homescreen. Can you verify?

It's a great solution for on-device customisation you wouldn't otherwise have, and behaves well for kiosk deployments as well as just offering a consistent, unified Android home experience irrespective of OS or OEM you may be deploying 🙂

This'll go well as a standalone topic 🙂

I imagine for your use case setting up conditional access policies would help here in addition to app protection policies. Conditional access is pretty aggressive in ensuring devices meet requirements frequently - at least on Android - and should help.