Following This article

Following This article
https://premium.wpmudev.org/blog/web-hosting-design-business-wordpress-multisite/
I've got a few questions, and they are detailed out here:
http://screenr.com/YlcH

Basically, If I click 'network enable' all of 'MY' WPMU plugins, is that going to make them show for all of my users as well?

And... tell me more about the "mu-plugins" folder? Is that where all of 'MY' premium WPMU plugins go, or is that where I put all my 'end-users' plugins? [I've used multisite several times, but never have I created a folder for plugins]