Fair enough. I did somr Santa's Grotto shots with my Fuji s5600, which looks to be not quite as good as yours, and it did very well. Ensure that you have it on the highest JPEG setting (forget RAW for this) and make sure that you understand the face detection functionality, and trial it beforehand. This should identify the faces in the shot and ensure the correct aperture and ISO/Flash/Shutter to get everyone sharp.
Try some test setups at home first, and then some more on the night, and have a plan for what you are going to try out. I'd say that a tripod is essential to maximise sharpness, and be prepared to post process in terms of brightness, contrast, noise and sharpness to make the best of the images that you get.
I would be aiming for a relatively low ISO, to keep noise down (ISO 200), the flash with red-eye enabled, an aperture in the middle of the range. Try it out and if the shots are too dark then open your aperture and drop your shutter speed accordingly to compensate.
If the worst happens and you get horribly confused then just stick it on auto or portrait and see how you go. Better to get reasonable shots than end up with a card full of rubbish because you've lost the plot.
Enjoy yourself, it can be a real buzz
