Vivenne of Cavall is the wife of Wyldon of Cavall, knight and training master of Tortall. They have four daughters: Eiralys, Sunarine, Cathrea and Margarry of Cavall. Vivenne's son-in-law is Owen of Jesslaw through his marriage to Margarry. Her sister-in-law, Elasabenne of Cavall, doesn't particularly like her as she doesn't think that she was good enough for Wyldon.
Only on one occasion has Pierce spelled her name like "Vivienne" - the rest of the time she has spelled it Vivenne, so it was probably a typo.
? │ ┌———————————————————┴—————————————————————┬——————————————————┐ │ │ │ Wyldon of Cavall ┬ Vivienne of Cavall unnamed brother Elasabenne of Cavall - unnamed husband │ ┌—————————┴———————————————————————┬——————————————————┬———————————————————┐ │ │ │ │ Eiralys of Cavall ┬ unnamed husband Sunarine of Cavall Cathrea of Cavall Margarry of Cavall - Owen of Jesslaw │ unnamed children