There's a good list of all the HTML 4.0 entities here: http://www.w3schools.com/html/html_entitiesref.asp
I whipped up some quick standard actions (attached) to replace the most common entities (', ", &, <, >, , ©), and it works well enough for now. Do you think you could add the functionality to run actions within the web sources dialogs (the "Adjust Tag-information" one at least)? That would save some time.
Also, I noticed the Musicbrainz script wasn't grabbing the year for some reason (on pretty much any album I tried), so I fixed it by doing another findline command before the findinline command (and adding some more text to search for). Also, debugging was on, so I turned it off. I've attached the fixed script below.
Standard.mta (883 Bytes)
musicbrainz.src (2.92 KB)