Hi Danilo,
The newsletter is defaulted to false to require opt in. Its not currently possible to make it default to true but maybe sometime we will implement support for that.
The timezone will default to the timezone that matches this setting in Web.config:
<add key="PreferredGreenwichMeantimeOffset" value="-4.00" />
Sorry but Event Calendar Pro does not support the scenario you are looking for, if the user can edit the calendar they can edit anything in the calendar, its not per user. I think "Appointment Scheduling" is a different animal than "Event Publishing", I plan at some point to make a Resource Scheduler Pro for booking conference rooms or appointments or any resource, but I think it will be a separate product than Event Calendar Pro.
Best,
Joe