Yes, it's important that every Event Input plugin track has the I/O Utility plugin as insert effect, set to Output 1-2, then Bypassed. Same with every Audio Input plugin track by the way. This is crucial for proper functionality.
If you want to have the same latency when playing from an Event Input plugin, you can also put the I/O Utility plugin on the main VE Pro plugin track to put it in Live mode. Note however that Logic throws all Live mode tracks processing on a single CPU core, so it is possible that you run into performance issues in some circumstances. The latency when playing from an Event Input track can also be reduced by setting Process Buffer Range to Small (instead of inserting the I/O Utility plugin on the main VE Pro plugin track).
Also make sure you're using the latest version of VE Pro 5 (currently 5.0.9753).
In terms of automation: The Event Input plugin has 512 automatable parameters (Param1 to Param512). Say you assign "Parameter 1" to "1 Master Bus/Volume" in the Automation Mapping window in VE Pro. The volume slider in the master bus will then work like any automatable parameter in a regular AU in Logic. So Param1 of the Event Input plugin that has "Use for automation" enabled directly represents the volume of the master bus in VE Pro.