Well, I added the Mongol Military Government (U68) for 0.60. Here are my design notes:
Mongol Military Government:
User province 2605 in province.csv as off-map province
Added name in world_names.csv
Added Description in scenario_text.csv
Added .inc file
Added u68_1936.ai file including dummy
Added leader, minister and TT file
gfx see below
Added event file, coded Suiyuan campaign events
Added U68 propaganda poster (=MEN)
Added U68 flag,shield and counter (=MEN)
In your case, you´d have to add a revolter. Find out empty minister and leader numbers. Provide an event file and make it a CORE-ish event file with mobilisation events etc.
When 0.60 becomes available for public beta, have a look at what I did for U68.