Provide both spouses’ birth records, the marriage evidence and the proposed immigration sequence, together with the other records the case requires.
Explain the exception being relied upon
The analysis should identify the legal exception and its conditions rather than simply substitute one spouse’s country on a form. Consistent civil records support that assessment but do not guarantee acceptance. Assemble the records that would let someone unfamiliar with the family reconstruct the claim without asking a question.
Both birth records establish the two birthplaces; the marriage evidence establishes the relationship the exception runs through; and a clear statement of who is the principal, who accompanies and who follows establishes the sequence the exception has to fit. Missing any one of the three turns an assessment into correspondence. Where one civil record is inconsistent with another, deal with it directly rather than filing both and hoping the difference passes unnoticed: a name spelled differently across documents from two countries is common and explicable, but it is explained either by the applicant or by a reader's assumption.
Where a record cannot be obtained at all, say so early and ask what secondary evidence is appropriate, because that question has an established answer and finding it late is what turns a document problem into a scheduling problem.