1) There is currently no combat, so it wouldn't really do much. Once we have combat, then party sizes will dictate how many you can control at once (and currently do anyway, in fact). There has been talk of other measures to protect newbies in starting cities.
2) May I refer you to the Rules pages, linked at the top of every page? Specifically the section of Faction Creation.
3) Once again I refer you to the Rules, this time the page for Governments, under the Economy header.
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"May the Grace of Ara go with you, and His Vengeance be wrought upon your enemies."
Well Barret Zem, you join a goverment first, then apply to their I beleive Internal Affairs each goverment calls it something different. Then you will have to be selected to be a recruitment officer. Yes the only way to take over a planet will be to build Flats or PRs. I doubt you can as you are a new player as all the planets are already taken over, sorry to squash your dreams, but alot of new players think this as well.
Also if you hadn't already, please take a look at the guide.
There is a LOT of groundwork you need to do before you could possibly have your own government. Moreover than a planet, you will in fact need to control your own SECTOR. Now, you might be able to find someone willing to sell you a planet, once you've earned enough money to pay the going price for them, but taking control of a sector is going to take a LOT more work, and probably either some incredible diplomacy, or making best friends with an existing government leader who has multiple sectors and decides to let you have one.
I'm not suggesting you abandon your goal, but I highly suggest you set yourself some lower, simpler, interim goals towards reaching it.
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"May the Grace of Ara go with you, and His Vengeance be wrought upon your enemies."
At this point, you may want to consider just working your way up through an existing government to put yourself in a position to lead it when the leader steps down for other reasons. It is likely the most viable means, if your goal is to control a government faction. Generally, most goals in SWC can take considerable time, though, so don't expect to be able to accomplish this quickly. Otherwise you may need to work on your collection of assets to tackle this come combat. :p