I assume you can book the ticket in her married name by doing it over the phone rather than online.

While you can apply in advance to get a passport in your married name, I believe that it doesn't start to be valid until the date of the wedding and so there may be an issue if this causes her old passport to expire when she still has travel booked in her maiden name. How long do you have between the last date of travel booked for her and the wedding?

I went on honeymoon with tickets and passport in my maiden name just because I thought it was easier, tbh.