If I assign Event Managers for some events, do I still have access to all the information?

Yes, as a Community Manager, you see everything! (Well... not dead people!) {ref Sixth Sense, in case you're freaked out!} 

Only Community managers can create new events or copy events. However, once you have created the event and assigned the Event Manager, they get to edit it and add tasks, assign helpers and so on. Community Managers also continue to have edit rights on all event, activities, tasks and conversations.