sorry for a lot of wonder guard question, but just for sure... does it hit Sableye wonder guard? i read this http://bulbapedia.bulbagarden.net/wiki/Wonder_Guard_(ability) is it true?
Firstly, Sableye can't have Wonder Guard without hacking (that would be pretty unfair!)
But, based on that bulbapedia link, yes, it would hit Sableye even though it is not effective. Also see the link DarkTyphlosion posted.
No, Sableye has no x 2 or x 4 weaknesses, so no attacking moves could hit it under normal circumstances (The exceptions are Future Sight and Doom Desire).
And since the whole attack is nullified, there is no chance of burning from Fire Fang. The only way to burn WG Sableye is through Will-o-Wisp.