You really should start looking into this thing called Google, and compile some sites as your resources.
www.ratemyserver.netirowiki.org
to start you off.
1. Effective leeching requires a lot of gear or a good computer for multi-logging. Yes they can WoE, they can do all the kinds. They are very effective acting as a breaker and e-caller, good for leading a guild. Warmth does not work for the Emp and does not do HP dmg to players, but it drains SP instead. They will be mostly DPSing, though I'm not too familiar w/ the strategies involved, unless we're talking restricted NT :|
2. SQI first, but that's a lot more expensive than Kahos. There's not much use for Eddga imo, since you can move around with Flying Side Kick, Running, and High Jump.
3. DracPhreeAbysmalKnight book for PvM, PvP/WoE I would guess DopTH? or TTH?
5. Buying is usually cheaper, especially if it's already carded.
6. Only your Kid or FAMILY without level limit. Essentially, you always need the kid in the party (and online) to share. Though last time I checked it didn't work, after we moved to eA
7. max stat=80; half MHP/MSP; -30% forging/potion creation chance; counts as small rather than medium
8. You can't trade it or store it
9. You can collect treasure boxes at the end of every day, the number of boxes depend on your economy investment. Read more in irowiki, search WoE
10. No idea
11. Yes, read the skill list in irowiki, rms, or playragnarok (official server site)
12. Google
13. Depends on how organized the guild is
14. No
15. Evil Snake Lord