Hi D,
Thanks for your interest in our plugins. Yes, they are MU-compatible. You’ll be able to install it on your network site, put in the license key there, and then use it on that site and/or sub-sites.
We ask that people with multi-sites purchase a license equivalent to how many sites/sub-sites they’ll be using it on. You can read the details here. If you are only using the license on your one network site, you’ll only need the Personal level license. The others do not come with any additional access, except that you can use the license on multiple sites. Does that answer your question?
Best,
Leah