Woah! Thanks for the detailed reply and I get you're trying not to give it all awayConsequences level: Paramount. (It's basically a main quest level decision.)
Currently existing Republic remains in charge. (No. There will be more than just a pat. It's a main quest either way.)
If you don't do he questline. She is essentially just another member of the household
If you do..
You topple the Republic, it's getting replaced with a new and how that functions depends how you built up Aria.
The New Republic depends heavily on what stats you set her on the throne with.
YES. Raise her stats.
Important to note.
Corruption high = It will be largely the same Republic.
Corruption low = Liberation/Democracy/EndOfSlavery
Mostly remains.
No. All depends how much you support her (whether you do her quest or not) and those required stats because those will effect how well she'll be able to govern the new republic. (Again. Cannot overstate the importance of corruption stat.)
One more question though, if I do support her. Will I lose access to Kymanto? Should I purchase all the other slaves before hand otherwise lose access to them kind of thing?
Also, for the Mastersphere, you said largely the same. Again same question, and I guess that question can be extended to in general. Is there anything I should do before starting the rebellion that I can't do after the rebellion is started/done?