Personally, I'd carry. You're not at any of their homes, you're in a restaurant, and that makes a difference. If I was going to somebody's home I didn't know, then I might decide to not do so out of courtesy, but any public place or any restaurant "that you can carry in" is fair game to me, no matter who's going to be there. Another deciding factor would be the fact that you guys are the ones throwing the party. To me, that puts the ball in your court on the issue.
Btw, good luck on getting your CHP in a timely manner. I just called to schedule an appointment with the sheriffs office yesterday, just to go in and apply, and that's not even going to be until May 4th... So I should see mine in August . Hopefully it'll be better out in your area.