Professional immigration issues, experts first.

If you don't disappear automatically, you are obliged to return your China passport to the foreign embassy in China, but if you don't, no one will ask you for it. When you apply for sworn citizenship in Canada, people here will tell you that Canada recognizes dual citizenship, but some countries do not. You are advised to use your Canadian passport when entering or leaving any country to avoid disputes, but the Canadian government has no right to confiscate your China passport.

Your property in China is your private property, and the government will not confiscate it without reason.