So, judging from what we have seen so far, Double has an attack originally intended for Cerebella that more or less references R. Mika’s butt charge, Mike mentions this works somewhat like Cere’s run. Double also seems to get to fire Parasoul’s gun. She also has several interesting normals like what seems to be Fortune’s launcher, Parasoul’s Ken kick and so on. In addition her grab seems to be entirely her own, while one of her supers is Peacock’s scrapped car super. Anyone else hoping for an amazing, squishy command grab? Failing that, at least getting a copied one. Also, while she’s quite large her dash also seems to go really far very quickly.
EDIT: Well crap, most of this is on the wiki, oh well. Her launcher being named Impawster is kind of funny.