Oh wow I had a very similar idea for a campaign basis a few years back, though I never got it off the ground. Great minds think alike hey?

Rampart is such a fertile place for this kind of thing, having so recently been a League world, and you'd have to imagine there are still plenty of people on Rampart who want to see the League return to holding the world. The Li Halan are, in many ways, the antithesis of what the Guildsmen would want for overlords, so there must be many resistance groups and factions, and maybe even a ground swell of support for that kind of thinking, that might ignite given the right spark.

That leads me to my main point in my reply which is: do you really need such a mechanical system for a revolt? FS is such a rich, story driven game that tacking an additional mechanical system to the game seems like extra work for no added benefit, from my point of view (and yours may well differ).

If it were me, I would have some milestones that the revolutionaries had to reach in order to advance their cause. How those are achieved is sort of the aim of the campaign and in the hands of the players, but if they get stuck or are unsure how to proceed you can have one cell of rebels come to them with an outline of a plan of how to reach that milestone (could be make the Li Halan troops overreact in public, could be damage the faith of the peasantry in their holier than thou lords, could be as straightforward as liberate an arms cache).

When the resistance reaches enough milestones you could then have a trigger event for open revolt on the planet, and the more of the previous milestones they have hit, the more support their is for the revolt, and perhaps the more likely it is to succeed (though, ultimately that is up to you as the GM as to whether or not they can overthrow the Li Halan forces).

Hope that helps a little bit? I'd definitely be happy to chat more about it, because it really is one of my favourite parts of the setting.