General Plugin activation questions

Can I please ask 2 generic WP multi-site plugin questions:
1. Can a plugin be made available for admin use only from the admin homesite dashboard and not network wide? (some og the plugins on here for example I would use for site set up but not want available for network wide distribution.
2. I am confused by the network activate function! I have previously activated new plugins from the admin network dashboard but some have not appeared on the plugin list on the admins homesite. I am not seeing any other activation choices other than network activate or deactivate. Is that right?