you can try from zhanxi road market and other markets around railway station, and try from shangxia jiulou night market...
i have no idea about that brands for the camira.you can try from Nanfang building and from New aisia electronic products wholesale building....
yes it will be open during that days.
you can fill a form ,put your name and passport number in it. then they take a copy of passport then give you a acount card
have nice trip