Max Shutter speed
Leica C-Lux can shoot continuously at max speed of
10.0 fps and has max shutter speed of
1/2000 sec. C-Lux also has an electronic shutter which can shoot silently at max speed of
1/16000s. One thing to keep in mind is that electronic shutter may cause rolling shutter / jello effects, and also banding issues under artificial light on your images.
Flash
Unfortunately C-Lux doesn't have an external flash shoe so you are limited with the built-in flash.
Focusing
Leica C-Lux features a Contrast Detection autofocusing system. The AF system has 49 points to choose from. Leica C-Lux also features
Face detection AF where it intelligently detects the faces in the frame and locks the focus automatically.