You absolutely cannot reference master from another database, so that won't work at all (currently, wait until the Instance as a Service is released, that could change). My immediate though...

Using SQL Monitor, you can sort the queries by duration, waits, several different ways.  If you use the top of the screen to highlight a particular time range, say the...

Can you use Agent? You could run a PowerShell script to remove it that way.

I'm with HanShi. If it's the exact same version and edition, the only maintenance that's really necessary after a restore is a CHECKDB. There's not going to be anything else...

Considering the amount of mixed technology you're dealing with, I don't have a simple solution for you. The one thing I can add to the conversation, I would absolutely do...

Pretty much this, DATEADD, on the columns in your predicate is going to lead to table scans which will absolutely lead to poor performance overall. You'd be better off with...

Depends on where the backups are stored really. If you're backing up to your production server, copy then restore, always (and stop backing up directly to the production server). If...

Pretty sure you already know the answer.

The email service on SQL Server was only ever really intended to act as an alerting mechanism for issues on the...

I'd go straight to PowerShell for this. You can run the query, output it to a result set. Use the result set to delete the files. Way too simple.