IGN posted up a story stating that the ''Ashley Graham'' character that so many people were dead-set on, is actually Sherry Birkin, the little girl (who will at least be 22 by RE6, if that ''10 years after the Raccoon City incident'' time-line is the same across all stories) from RE2 with a unique form of domestic abuse to get over--her dad turned into a ever-mutating monster who ''impregnated'' her with his embryo (which was mostly destroyed..), and her mother was crazy bint who apparently thought the extra four spikes protruding out of her husband was a good look for him. Also she was very distant with her daughter, just to put a cherry on top.
Anywhoo it would kinda make sense if this is Sherry. Both Sherry and Steve were eventually plucked up by Wesker across the story, so if the new guy does turn out to be Steve, then it could mean that the two built up a bond, escaped whoever knows when, became mercenaries for whatever reason, were taught Martial Arts by Jackie Chan, and BAM.... well, by BAM, I mean whatever they get up in RE6.
That's only going along with the theory that it is Steve, though, but whether or not the woman is Sherry Birkin seems pretty much solidified. IGN were spot on with their information about the trailer before the trailer was posted, so I think it's fair to trust 'em about this as well.
Finally bringing back Sherry to the story certainly took them along enough in any case; she was initially planned to star in RE5 as the ''Bird Lady'' instead of Jill, but instead they replaced her with Jill because pfffffttt fuck knows.