1) I wouldn't start higher than $50 buyin, but any buyin below that is fine until you have a really good idea of your skills.  It's perfectly fine to start in the 20s, for example.
2) 60% is possible, especially in the low to mid stakes regular speeds on FTP or Stars.  I would shoot for a 10% ROI and go from there.
3) If you like regular speeds, play those.  Turbos go much faster, but your edge is smaller, meaning more variance.  Many new players start with regular speeds and once they are comfortable move to turbos.  There are still plenty of players who play regular speeds primarily, including many 6 figure winners.  Dibasio and Croixdawg come to mind, even though they both do play turbo speeds.
4) May be true.  In my experience the players are weak in both structures though.
5) If you're going to use Sharkscope I think it's worth it at almost any level.  It can give you an initial idea of what kind of quality opponent you are up against.  This is pretty big, especially early on.  Your decisions against a -20% ROI player in the low stakes will probably differ from your decisions vs a 10% high stakes winner.
6) I wouldn't google around too much, there is a lot of misinformation out there about heads up sngs, even on sites that you would expect to be reputable.  We have an article on bankroll management that might be helpful to look at.  On my coaching page I have links to at least 2 articles near the bottom of that page that can probably help you as well.  My end game video shows users how to use Nash in a good way in the end game, Primo also covers some end game in a few of his videos as does Croix.  The 2p2 Heads Up Forum is also a good place to ask questions (along with this forum and the member forums).
 
Good luck.

for the bankroll considderation imo it all depends on how much you are willing to risk to learn the game. If you dont really mind losing losing a bunch of money at the start you can start at the $30s or the $50s since your roll is big enough to play those. But personally I like to start off at the $10s untill you start getting comfortable at playing HU SnG and the start to move up really quick.
Deciding whether to play the turbo's or the reg speeds all depends on whether you think your edge comes from playing postflop or playing preflop. So since your a cashgame player I suggest you should play the reg speeds unless you used to shortstacking them.
http://www.holdemresources.net/hr/sngs/hune.html here is the nash chart you can use for the endgame, but I usually wait till around 10-12BB to start using it since you can easily get a bigger edge playing the fish postflop at 13BB+.

 Trippy, you seem to have things down... are you beating $115+ yet? PM me.

First, if you play on FT, I'd suggest to start playing regular speed tournaments. FT's structure is faster then Stars, so regular speeds are not so boring. In turbos you will face more variance and it will take more time to define your actual roi / winrate / ability to beat the current limit.
If you have 3K, you can start at 10$ or 20$. You need to get some basic experience how to beat bad passive players. At the $30s you will see many agressive guys. They are still bad, but very agressive - bluffing, 3betting, light 4betting etc.
I dont think you have to worry about your winrate at low buyins (30 and low), and you dont need to play tons of games at any level. If you feel that you are good at this level, move up.
At the $50s it's possible to have ROI 13-15% and even higher. This is probably first level comparable with your bankroll and a first level when you can win / loss serious money. 
Sharkscope (or other database site) is very very useful. It's only 42$ /3 month for the 150 searches/day. However, you should remember that SS is not officially allowed on FT. You will use it for your own risk.
Beside SS it's very helpful to mark opponents (using color system) and make notes on them, like in xSCWx's videos.