I have been relatively sedentary during this time except for activities of daily living. I feel like if I start being active it will just flare up bad again. They occur most often after acute trauma. Most often, spondylolysis in young adults and adolescents is non painful. There is usually an associated slipping or spondylolisthesis which can cause pain.
Treatment is conservative, with bracing, rest, anti-inflmmatory agents, and flexion bias exercises.
I don't have the exact number on how long one should wear the brace. However, I think that 6 weeks to 2 months should be suffice for the fractures to heal. It is possible that your back pain could be from the resultant stress placed on the lumbar disc at the time of the fracture. Though disc herniation is rare in spondylolisthesis, an internal disc rupture or annular tear is not entirely implausible. This could explain for your leg pain initially.