1. That depends on the situation: I've seen flash that had nice drawings, but hardly had any animation at all. (Arrogancy and those Motion Comic flashes come to mind.) On the other hand, I've seen flash cartoons that were poorly-drawn, but were well animated. (Roger Van Der Weide and Doug Sauncy come to mind.) This very question is one of the reasons why I haven't made a complete flash yet, just test animations.
2. Look up McFretN, Krinkels, and Razzo.
3. For my test animations, 21 to 24 frames per second.
4. I usually think it up in my head, because I tend to get writer's block.
5. I storyboard my stuff on paper or in flash itself.
6. A bit of both.
7. Depends on the situation. On one hand, I import as much of the sound that I can before I get to animating. On the other, If it's just a test sound goes in later. There are times when you need the parts before you get to work.
8. Enough to make some simple space shooter and platforming mechanics.
9. Already been answered.
10. Too many to mention. For Big names: Ralph Bakshi (I have to agree with what Lenkobiscuit has said), Tex Avery, John Sparey, The Fleischer Brothers, Fist of the North Star (best anime ever), Todd McFarlane, Mike Judge, Riki-Oh, Satoshi Urushihara, Renaissance (2007 rotoscope film), and Ark (best animated film that you missed out on).
For NG users: Evil Dave, Mindchamber, McFretN, Helbereth, Kong, Krinkels, Sto0g3, Dean Packis, Doug Sauncy, Ben Spurgin, the Bunnykill guys, Dave Lovelace, Fat Dime Studios, Piconjo: Besitzen Sie, Retro Mike, Alvin Earthworm (even though his jokes are terrible), Blordow (I think he should stop getting his thoughts spoonfed to him by the likes of Rtil), Daniel Sun, Clark Lybeck, Randy Solem, Rick Marin, and All Fads Die.
11. Yes, it looks nice.
12. I Dream in Retro, The Undead, Serpent's Grave, and Banned Slim Jim Ad.
13. See Number ten for details.
14. Look up "The Fox and the Mirror" on here.
15. I discovered ConceptArt.org from Zanroth and when I started posting, I got helpful advice and started to working on what needed to be worked upon. Now, I've seen a bit of improvement in my work. I recommend that you check that site out because the forums are great and you'll find Rick Marin, Zwickel, and Egoraptor there as well.
No ammount of style/animation/length/originality can compensate for bad content. (Throwback the Duck, Tarboy, both of the Nin10Doh! collabs, and Cupid VS Hate Demons spring to mind.) To quote Gamerman 555 from GameFAQs: "Being Original is good, but only if the idea works."
It isn't the medium used (Example: Imported video), but the quality of the final product (Most of the claymation/stop-motion stuff comes to mind).
BeamShank
As far as deciding which of many projects to do, think about this. Don't just think about what you want to make most, but consider doing a less favorite idea first, and the end result of the animation you didn't pick first will be better due to practice. I've been sitting on something I wanna make for 2 YEARS. and I'm juuuust nearly ready... but not before I knock away some more projects.