It says that you can only edit your own tracks. Usually, people work on their tracks. If you want to take over, you duplicate those tracks and the previous owner may or may not remove them from the project. This is how VST Transit maintains synchronisation, otherwise different project members run into different states and clashes occur.
Tempo should work (make sure to have the latest version), Midi Data are sync’d, what problems do you have? Same for instrument selection afaik, automation is in the making.
Sure, when he creates new tracks in whichever way, they are his tracks and added to the project.
I don’t know what you mean by “revised”, though. If he and his tracks were already added to the project and he merely changed those already exsisting tracks, sync should just update these tracks and not add them (and so far it hasn’t).
Let me repeat the simple strategy of VST Transit: sync will upload your changes (which you can only make to your own tracks) and download changes of all other members’ tracks and merge these. This way all potential clashes are beeing prevented. To take on ownership of somebody elses tracks yes, you will have to make a copy so to make those tracks become yours and eventually the previous owner may delete them. If you do this process repeatedly, I would suggest that the two of you keep their own sets of tracks (so there’s two sets of tracks), but usually one person works on one instrument or voice. And if for instance he plays the bass in the verse, and you play it in the chorus, you’d create 2 bass tracks.
In no case should revised tracks be doubled by the system, and so far we haven’t observed this to happen.
VST Transit transfers “finished” tracks only as of now, so you’d have to freeze those tracks beforehand.
It depends. The more “specialized” features you use, the more complex generic cloud project sharing becomes. And it depends on your workflow which I didn’t quite get yet, because usually transferring ownership of tracks doesn’t appear that often. VST Transit attempts to keep things simple for interchanging of “standard” tracks. If this doesn’t apply at all to your workflow, you have to either find a way to adjust it, or to use “oldschool” data transfer instead.