Agree with kingweb and JF0.
Just off the top of my head, your one requirement that pushes you out of "normal" WordPress territory and into the bigger CMS systems is:
"Each venue will have an admin account that can be used to create/modify their events (an no one else's)"
That, combined with the somewhat persnickity needs for the events would probably defeat any standard plugin. However, thinking laterally, you might get what you need out of BuddyPress...