Hi - unfortunately, no one can give you odds regarding the likelihood of testing positive for systemic sclerosis, or know for certain what her future will be. It sounds like the tests are showing that she likely has an autoimmune diseases of some kind, and the course and nature of disease can vary a lot from person-to-person.
Here is a bit of info on systemic sclerosis: https://www.healthline.com/health/scleroderma#fa-qs
In addition to the tests she is having, the doctors will examine her physically for signs of skin or organ involvement. The level of involvement and the current state of disease progression will play a big part in treatment and longevity.
Here's about the first question:
https://www.mayoclinic.org/tests-procedures/ana-test/about/pac-20385204