CoursePress theme on single site without network activating

i would like to use CoursePress on a site in a multisite.
I would prefer not to network activate it so CoursePress won't be installed on all the other sites but just the one site required (not main site).
However when I do not network activate the plugin, i do not get access to the CoursePress theme.
It seems to me that i have to network activate the plugin for the theme to appear in the network admin and then also network activate the theme for it to be available in the required site.

Do i have to install ProSites to have the flexibility i am looking for to, not network activate the plugin, activate the plugin on just the site required and have theme also available for that site ?

i hope i have explained myself clearly.
look forward to your kind support and assistance.