The first, FilesMatch "." will deny access to every file. I would by the way say this is wrong, since . will only match any character once... and it is not likely that we will have files with one letter names :)
The next one will allow access to known ezpublish files, only the ones that can be directly requested from the browser.
Nope, but you can fix it by replacing "." with ".+"
Actually I need to start thinking straight: "." will match any file, no need for a + here, since there are no ^ nor $. So you can leave it as it is, it is correct.