Since you are meeting in a restaurant, you should feel pretty comfortable with whatever happens - it's a public venue and you can easily leave if and when you want.
Some meet-up organizers have a very specific agenda, some don't, and some have a few topics that they'd like to discuss.
I have found that there are a few ex-jws that attend these events are looking to convert people to their new-found religion.
My preference is a more free-style affair where people can present a specific topic that is pertinent to their person growth away from the control of the WTS. One night part of discussion was on voting: How to register; General descriptions of the various political parties; etc. Another time during christmas was about 'how-to' decorate.
PEC and BarbieDoll have had a few meet-ups at their home. These were much less formal and more about friendship and socializing.
Have a good time!! And please do tell us how it went for you.
-Denise.