I agree, the finished product is quite nice. Strix is accepted. 

Mat, your sheet is progressing nicely. But Arachnid needs to have some kind of personal shortcoming that makes a team dynamic an interesting proposition. Sure she has a checkered past but that doesn't really mean much if she has no personal flaws now. And I personally think her super-strength is a bit too high, especially since currently the only people stronger in the RP are a Superman-type and a gargantuan mass-changing metal man. That much strength in a highly agile form almost makes all the other melee-types besides Neutro look superfluous. Her strength should be downgraded to be more on the same level as fighters like SilverWolf and Blast Girl. Even without being able to lift five tons, she can get a lot of traction out of wall-crawling and shooting webs. 

Also you're going to have to offer a plausible-sounding explanation for how she got her powers from those spiders. But it really might be easier just to say she's not a freak lab accident but that the Awakening occurred right after she was bitten by the spiders, and whatever changed the spiders combined with the completely mysterious forces of the Awakening changed her into one of the most unique Metahumans around. Food for thought.