New on-premise AD, New Azure AD, existing Google Education Workspace

I've recently been appointed Technology Coordinator at a private school. They have a well-established Google Workspace for Eduction account and a multi-device environment. Naturally, I want a single user name and password for all of this. If I could start a new Google Workspace account, this would be easy, but I can't. This is my first time working with gsuite/Workspace.
Here are my questions:
1) If I set up users in AD exactly as they are in Workspace, let that populate Azure AD, will the new passwords from AD modify the existing accounts in Workspace?
2) Does my AD OU structure have to exactly match the OU structure in Workspace?
3) What other considerations are there?

A diagram of what I want to accomplish is below. Everything is new except for Workspace.