There are people using it already. Inside and outside of Google. http://flutter.io/
No, flutter is still in tech preview mode. There are working example demos in the codebase but that's it. I have no idea on their release schedule but my guess is that Q1 of 2017 can be a target for a beta release.
Probably you mixed Flutter with Dart.
Nope. I also don't think that our statements are at odds with each other. Flutter isn't done yet but that isn't preventing a lot of folks from using it for real work.