It's not a must, just a suggestion; i know a lot, and without an arrogant ...
Anyone who 'has a connection' to Fryslân is welcome as a Frisian. Of course, we're delighted if you have a link to Fryslân. For example, your event might take place in Fryslân, or maybe you live here or your event is related to Fryslân.
No, there is no specific requirement to speak Frisian. You can hold your event in Dutch, Frisian, English or German, or another language you may speak. Indicate which languages you speak when you create your profile.
No, events that you offer are on a voluntary basis and, as such, they are free. If you incur expenses, such as buying a cup of coffee if you meet in a café or a ticket to a museum.