2. The patent certificate can only prove the legal status of the patent on the date of authorization. Theoretically, the loss of the certificate has no effect on the patent transfer.
What you need is to ask China National Intellectual Property Administration for a copy of the patent register. You can find it on the "Home Page" of China National Intellectual Property Administration's website. Special column > public inquiry service of patent examination process > handling guide > see "file copying" column for specific handling requirements.