The attire for most Chinese wedding banquets is Business-formal/business cocktail unless stated otherwise. Dressier cocktail and black-tie+ formal dress attire is usually what the bride and the family wears. Nothing overtly sexy and if in doubt, err on the side of conservative. Red and gold are the the bride and groom's colours. The bride may opt to also wear a western wedding dress too for part of the evening with several change of outfits symbolizing dowry. Black for women may or may not be ok depending on how cosmopolitan the family is. If in doubt, ask. Pearls are fine but are generally not seen as a statement/investment piece as they are outside of the Mainland. However, if they compliment your dress, do wear them. Just don't be shocked if some someone makes a tackless comment.

The banquet itself may be either a formal Cantonese service (Russian Service) where each dish is brought out as it is prepared and the service is synchronised with each table or it may be "mainland style" where all the dishes are brought out all at once when they are ready. There might be some grumbling amongst some Mainland guests as some people will claim to be "hungry" during a Cantonese service when they actually mean that they don't like to wait to eat.

+ 1 on the cash gift. Put it in a red envelope and write a short but sweet congratulatory message with your name on the back of the envelope. This is especially important if you are gifting a significant amount.

While the move-in gift would be appreciated, it would be might be best to consider that a housewarming gift rather than part of a wedding gift.

Enjoy your trip.