I've something very much like that in my grand story.

Saplings commonly grow from old stumps.

A new justice system would likely need to grow within the existing ecosystem for a while get established then gradually kill the old.

There were Native American systems before there was French and English justice systems and all 3 co-existed in North America for some time before America took over.

Even now, Military justice is very different than the common justice system. And they very from state to state, as well as internationally. Further there's different justice for middle class, the rich, and the poor.

I see an open justice system developed being the foundation of a legitimate (not manufactured by elites) revolution.