My family and I travel to China in july. Do we have to be present the 4 of us to get the visa?

According the travelagency we will receive our documents for applying a visum to your country only 3 weeks for departure. I understood they have to provide us with the hotelbooking and the return flight ticket in order to get a valid visum. Is this correct? Does the application form on your embassy website has to be filled in and brought along with 4 photos?
If you need a translater to attend all questions in dutch, french or german - the languages of your host country - I am at your disposal. Perhaps in this way I can avoid a lot of questions and make the China Embassy site more accessible for Belgian citizens.