I salute the OP for their effort to create a player driven story [up]
But from pure RP perspective i am strongly against the idea.
A group of settlers lead by noble ideas about freedom and equality starts a new colony... do you remember how the Empire was started and what we have now?
Lets think, what a colony dominated by former slaves would look like? I think it is safe to assume that slaves are the least educated part of the society. So very few capable scientist and engineers will be available. And, most likely, science and exploration wouldnt be considered priority by this new colony public opinion. Instead, strong anti-Bubble superpowers mood can be expected. This New World will consider the Old World, their former masters, as oppressive, anti-democratic and whatnot. So basically i expect them to be openly hostile. Populism will be everywhere, various activists will call for liberation of their still enslaved brothers in the Bubble. This is the perfect seed for a future intergalactic war.
Obviously this line of thought will occur to Bubble political leaders as well. And they will take the necessary steps to destroy this emerging threat while it is still weak. I can see a combined fleet of all three Bubble superpowers arriving at Colony and turning it to dust and ashes.
So, no. We dont need this. Slaves, no matter freed or not, have no place in this colony. And we dont need to create any kind of new world. Instead, we need to send there our best scientist and engineers. The Colony should stay politically neutral. It should be a place where Bubble superpowers cooperate peacefully for the benefit of the existing human civilization. In long term, this may create conditions for wars and conflicts in the Bubble to be put to an end.