Use the SQL Server Configuration Manager to add / modify any of the SQL service accounts. That will setup the appropriate permissions for the service accounts.

You need to grant View Server State for Activity Monitor.

You will need some sort of entitlement scripts for pulling out all those permissions.

This list is definitely NOT a one size fits all solution. This may work in my environment but may not in yours. Neither is this a comprehensive list.

As you...

Confidence is paramount, however being truthful about your skillset will help. A smart interviewer can immediately spot when someone is making things up.

You need to give them Alter Trace permissions

GRANT ALTER TRACE TO

I agree with the need to get senior management buy-in. I recently took over an environment with some of the issues you mentioned and more. I did a detailed analysis...

SQL Server creates local groups on the SQL box during installation (Under Computer Management --> Users and Groups --> Groups) as below

Default instance: SQLServerMSSQLUser$ComputerName$MSSQLSERVER

Named instance: SQLServerMSSQLUser$ComputerName$InstanceName

There are groups for Agent,...

Isn't your SQL service account part of the default local groups that SQL Server creates during install? If so, it should've had system administrator access to the instance.

No, the primary database can be mirrored to only one destination database. For the configuration you refer to you will need to use Replication

The default trace should be able to help you find out if there are file growths (event class 92 and 93) during the data loads.

Yes, if you want to use the new 2008 features.

Have you tried restarting the SQL services? Before that I would go in to the Agent properties and simply select database mail profile. I've noticed this as an issue when...

IMO,...

One way would be to move all the data to one file remove all the empty data files. Add the new files to the database with the sizes you need...