1) Calendar syncing is only available for your personal calendar. You cannot sync this to a events calendar that is displayed publicly like in a space or a group.
2) You can change the reminder intervals site-wide by editing the System Properties and changing the value of EventReminderIntervalInMinutesCSV.
3) You will have to coordinate with your own calendar, as any syncing is done with personal calendars in Communifire. You could possibly create a fictional user, however it would take up a user and count against your license total.
I hope this helps,Foster
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