I definitely believe it is Sherry Birkin over Ashley.
If you look closely their features are actually different, especially in the nose area. It's not Ashley.
As for the guy, I really don't think it's Alex Wesker... It very well could be Steve though and if that is the case then Claire better be in this game at some point! She has unfinished business with Sherry and Steve.
Yeah, not to mention, Ashley is more weak, timid and cautious, while this new girl appears to be the opposite...motivated and determined. I doubt they'd bring Ashley back, considering most people didn't like her, based on what I've seen, and there's been alot of fans wanting to see Sherry back. Makes more sense for it to be Sherry. Though I won't discount it being Ashley, since Capcom seems to ignore fan demand sometimes...