Synced Realm in AppGroup on iOS

Hello everyone,
I’ve got an iOS app using RealmSwift. I’m trying to set things up to access a realm from both the main app and a new Widget (iOS 14). I know how to do that, I need to migrate my realm file to a shared AppGroup container, but my problem is about syncing.

I want to be able to use in a future version of my app MongoDB Realm sync, and I’ve read many things about AppGroup and syncing Realms but everything is from when Realm wasn’t part of MongoDB.

So my question is, is it possible to migrate a realm file to a shared AppGroup container and still be able to sync it ?

And second question, is it possible to access current user connected from app extensions such as widgets ?

Thanks in advance !