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I-131 (AP) approval is irrelevant to I-130, but if the RFE is issued too soon and AP approval is too late, then your father may have no enough time to get the document in time (normally the RFE needs to be responded in 30 days).

One solution to this issue is that you may file I-130 for your mother first, your mother files her I-485 at the same time, then your mother get the AP to travel to China to get their marriage certificate.

You may file another I-130 for your father and your father file his I-485 one month or later after you file I-130 for your mother. Thus, when USCIS send the RFE for the marriage certificate, your mother may have got it from China.