This plugin allows you to create multiple levels of Super Admins in a multi-site configuration.
Please either hit me up on Twitter @cgrymala, report the issue in the WordPress Support Forums or post a comment on my website. If you e-mail me, please include "Extended Super Admins" in the subject line of the message. Thanks.
No. This plugin is only capable of removing privileges from a user. It cannot add extra privileges.
No. This plugin would be pointless for non-Multi-Site installations. It might actually generate errors if you try to use it on a site that doesn't have the multi-site capabilities turned on.
At this time, you can assign a user to multiple roles, but only the first role in the list will have an effect on that user's capabilities. In a future version, I will look into allowing multiple roles to modify a user's capabilities.
You can find descriptions of most of the capabilities in the WordPress codex.
Unfortunately, there is no definitive explanation for each and every capability, so you may have to do some testing and play around with things a bit to get things working exactly the way you want.
If either of those plugins is active, this plugin will attempt to use and save any and all of its settings across all of the networks. There is currently no way, with WPMN or Networks for WordPress activated, to use different settings on individual networks.
This plugin creates a new capability called "manage_esa_options". If you do not want a user to be able to modify the settings for this plugin, simply revoke that capability from any users that belong to the modified role(s).