have you looked at Hard Rock Café at Festival City... they have a private dining area upstairs that would be perfect for your number of guests and gives you the privacy yet you can still have all the ambient music/environment of the place... unfortunately they are a licensed facility but you can always speak to the management to ensure that drinks aren't served to anyone on the upstairs deck area
My 18yr old DD is organising a surprise party for a friend who's turning 19.There will be around 30 guests and we're looking for a non licensed restaurant with a fun atmosphere that can accommodate this number and serves spicey,tex mex,burgers,pizzas,wings, that kind of food.Has anyone had a good experience somewhere like this that they can share?