Put as much of the info they ask for as you can. If there are details you have forgotten and can't find out, just attach an explanation of this. As for old phone numbers that are no longer yours - just include them anyway. I did note in my form when the numbers were a cell phone.Explain your plans and offer whatever proof you can. You can get letters or affidavits from family members or friends if they will be helping you in any way when you first return - people who will be staying with their parents while they get reestablished get an affidavit from the parents about this, for example. You can show correspondence with potential employers, landlords, and real estate agents. You can show how you are planning to end your stay in China: for example, correspondance with moving companies or storage companies. Proof you and your wife have given notice at your current jobs. Proof you have told the children's schools they will be leaving and have made arrangements for their schooling in Canada.
