Yes. However, commits to the database must wait until the tables are unlocked. Bugzilla databases are typically very small, and backups routinely take less than a minute.
Yes. Look at http://link.GlobalGuideline.com for basic reporting facilities.
For more advanced reporting, I recommend hooking up a professional reporting package, such as Crystal Reports, and use ODBC to access the MySQL database. You can do a lot through the Query page of Bugzilla as well, but right now Advanced Reporting is much better accomplished through third-party utilities that can interface with the database directly.
Advanced Reporting is a Bugzilla 3.X proposed feature.
Email notification is user-configurable. The bug id and Topic of the bug report accompany each email notification, along with a list of the changes made.
Yes. Place yourself in the "cc" field of the bug you wish to monitor. Then change your "Notify me of changes to" field in the Email Settings tab of the User Preferences screen in Bugzilla to the "Only those bugs which I am listed on the CC line" option.