If Spider-Man is going to turn up in Captain America: CIvil War, Marvel needs to cast him ASAP - the movie shoots in two weeks. Even if the part is basically a cameo (which I suspect it is), they're going to want to have their player in place, and with a multi-film, ironclad contract.
I had heard from solid sources that Marvel was looking at some 16 and 17 year old actors; now a new (untested) source has chimed in to say that Mateus Ward, a child actor from Showtime's Weeds, auditioned for the role. It was so super secret they held the audition at a house, not any sort of office, but word leaks out, as it always will. Does this mean Ward will get the role? I don't know, and I'm not really familiar with the kid's work, but if true it does show that Marvel is indeed casting young. They don't want a Peter Parker (and look at Ward -he would be Peter Parker, not Miles Morales) turning 35 as they begin production on his third film. Like I said, this is a new source, but the information backs up other stuff I've been told by other sources I know well.
I've been very vocal about wanting Marvel to cast young for the role - I think a legitimately teenaged Peter Parker is a striking outsider when compared against the grown men playing Iron Man and Captain America. We've had 'high school Peter Parker' on film before, but this will be the first time it will be a truly high school aged actor playing the role, and that will visually pay off in spades.
Knowing that Marvel is certainly looking at 16/17 year olds, who would be your choice for the role?