[transmitthis]

For #2
You would be looking Edit Metadata in Bulk and the Search and Replace tab.

Search mode - Regular Expression have a play around with that, I'm no good Python Regexp, but someone will pop up and give you one, if you haven't already done it by then.


Or if I misunderstood what you meant by batch convert (you want to do many authors at once) you could do them individually just by Right clicking on Author Name in the Tag Browser panel on the left and choosing Rename!