Hello I'm a new player who has started a level 8 Drow Mage that will Multiclass in to the Rogue class. I hada few newbie questions that I need answered
If you are a newbie, you should not be creating an 8th level character. Yes, the rules allow this. No, it is still a very bady idea for the novice, as your questions tend to show. Of course, you may be trying to join an 8th level group and the ability to mix levels is not one of 4e's strong points. But even then it is no more than the less bad choice.
No, you should not be trying a multiclass. Now granted, the critics are right in saying everything in 4e is much the same once you get past the paint job. [They are just wrong in deeming this a flaw.] But you are still trying something that is easier to screw up, even if it is only marginally so. Better to go with a pure class for your first PC.
And that should be Rogue rather than Mage. Drow just don't make good mages. True, in my drow party, the wizard, if not dominating, was certainly pulling his weight, but he was the most skilled player we had. Since you have much to learn, you will likely end up as the party wimp. You may love the very idea of being a mage, but be warned. If you have any dreams of being the stud, select something else or abandon those dreams.
2)if a creature is caught in my Cloud of Darkness will it take a -10 penalty for being blinded AND I being totally obscured while in the cloud or just the -5 for the creature being blinded??
Very little stacks in 4e. If something is blinded, everything else becomes heavily obscured to it. The two are pretty much the same thing and there is no stacking.
3)I wish to multiclass rogue down the line and one ofthe feats allow me to get the sneak attack feature, would that count towards the spells I cast with my dagger?i also have light blade implement feat)
Check with your DM.
The text says "weapon", not "implement". The routine ruling is that "weaplements" swing both ways, but your DM might insist it is weapons only and can't be used as part of a spell attack. You can probably get a lot of people here to say he is wrong, but he is still the DM and is thus never wrong. Our opinions just don't count.