Re: political terminology
Regarding timescales: to some extent, it depends on how the state is already organised. Do the Twelve already have some ability to manage their own affairs in some policy areas? Does this include having dependant planets that take their lead?
If the structures allowing independent action already exist, different planets will develop differently and at different rates.
Try looking at the way different Warsaw Pact (and Comecon) countries were governed (e.g. Hungary as compared to the DDR). And also note that what an outside observer could have seen as a phony internal structure in the USSR - because the Union Republics were window dressing and everything was controlled from the Kremlin (or the Lubyanka), wasn't it? - developed almost overnight into fifteen more or less independent countries.
And something else you could see in the changes in Central and Eastern Europe: often the superstructure of democracy was put in place quite quickly; the development of democracy's healthy roots, and the creation of a civil society outside the control of the state, can take much longer. (And then there are those who just want to make a huge fortune....)