How does one write the name of a married female and spouse in a list of classmates?
One term sometimes used is the French word 'née' (meaning 'born', literally, but referring to the maiden name in this context). Hence:
Mrs Jane Smith (née Jones)
Mrs Cynthia Corning (née Stratton-Longbottom)
Etc.
I'm not sure whether 'Mrs' or 'Ms' is preferred when the context clearly shows that the lady is married. I'm old-fashioned enough to think it should be 'Mrs', but modern style might use 'Ms'. The referenced URL did not place brackets around the maiden name.
Also, in a list of classmates, the spouses would not not normally be given - the spouses were not, in general, part of the class. However, if you are listing the people invited to an event, you can decide how to display both the names of those invited and the names that would have been known when they were in the class. For example, you might have two columns, for example, the first listing one the 'Emily Post' approved forms, and the second listing the name that would have been used in class. That might be too arid for the context in which the list is to be used, though. You might list the class member's name, and then their spouse's name, if applicable:
Mrs Jane Smith (née Jones) and Mr John Smith
Mr Adam O'Hare and Mrs Susan O'Hare
This isn't the normal presentation, but the important information here is presumably the person who was in the class, and this shows that Jane Jones and Adam O'Hare were in the class but both are married. It is self-consistent as presented, but you might omit the first "O'Hare", I suppose.
The Emily Post Institute recognizes the following forms:
Ms. Jane Smith and Mr. John Smith
Jane and John Smith (informal)
Ms. Jane Johnson and Mr. John Smith
Drs. Jane and John Smith
Note that there is no informal form if the female uses her maiden name and that you should always use Ms. unless you know that Mrs. is preferred.
Also, the Emily Post Institute gives no formal guidance on whether or not to use the maiden name—however, it seems from various examples on their site that the husband's last name is preferred unless the wife has indicated otherwise.