This feature request is working its way through the backlog queue. No new details are available yet.
Q1 - not necessary - the folder structure was set up years ago, and there are hundreds of them that don't reflect how we work today.
Q2 - 9
Q3 - Creative Channels API? What is that? Seriously, we aren't going to learn something new just to make existing docs and folders available to in the Teams interface. We need a simple solution.
The way Teams works right now, it is fine if your real world team has just started and doesn't have any docs - the way the team works can be influenced by how Teams works. But for teams that already decided how they work, with hundreds of docs - Teams needs to be flexible to how they already work.
So let me create a Team without creating a new Sharepoint site, because I already have a Sharepoint site that is doing fine. I just want to integrate Teams into it.
You can add a Sharepoint library to the tabs, but not an existing Site. Many people have invested many YEARS developing existing sites in Sharepoint - they are more than just folders in a file system. Teams is great, but don't expect people to start from scratch when there is existing rich content. Allow us to add teams to existing Sharepoint *sites*, or even just a tab that opens an existing site allowing a quick way to reach existing content.
This feature is still in the works. No additional details are available at this time.
What Adren Shackelford describes is exactly the use case I was surprised I couldn't do.
If I already uploaded a file, it doesn't get any presence in Teams conversations. If I want to attach a file, there is an interface where I can select files already in Teams file containers. If I select one of those files to attach (actually I just want to provide a quick way to get to the file) I get an error message that the file has already been uploaded. Why does a UI exist to select files that have already been uploaded but then rejects those files on selection?
This is still being worked upon. I hope to have more details in the next couple months.
Please know the team is actively working on this feature.