We have two kids 13 and 8 year old.

I think it is too crowded for your 4 to stay in one room. Because the bed size in China hotels is not big. In a double room, it usually has a bed with 1.8m X 2.0m. In a twin room, it has two beds each with 1.2m X 2.0m. One room can only accommodate one extra bed with 0.9m X 2.0m. It is best to have a family suite or two rooms connected.