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.
You have no idea. Bugzilla's query interface, particularly with the advanced Boolean operators, is incredibly versatile.
Bugzilla does not lock records. It provides mid-air collision detection, and offers the offending user a choice of options to deal with the conflict.
You can call bug_email.pl directly from your aliases file, with an entry like this: bugzilla-daemon: "|/usr/local/bin/bugzilla/contrib/bug_email.pl"
Certain version of MySQL (notably, 3.23.29 and 3.23.30) accidentally disabled the "crypt()" function. This prevented MySQL from storing encrypted passwords. Upgrade to the "3.23 stable" version of MySQL and you should be good to go.