Updates all URLs in the database after moving your site from one domain to another.
Yes, you only have to run the plugin on each site.
The plugin handles it in options and postmeta tables.
URLs are only replaced when an exact match is found. Note that maching is case-sensitive. Be sure that you have entered the correct URL.
Some plugins store their content and settings in custom tables. Since every plugin's data structure can be different, we will not be able to update these tables, although it might contain URLs.
Yes, you can choose whether to update links for posts, excerpts, medias, custom fields, options and GUIDs.