You can do it by changing your advance setting of your virtual machine.
I not understand what you mean can you please send me a short description.
Currently there is no such option.
What is your use case? Perhaps you want administrator(s) to pre-configure workflow associations for all regular users?
Yes right the User only should have the rights to start workflow.
The problem at the time we implemented this functionality was that Web Client persistence API allowed file read/write operations on per user basis, meaning each user could read/write files only from its own disk folder. So if the admin makes some modifications and stores them, they won't be accessible to other users.