It's been like this for awhile actually, I fully believe most of the trailers following the Cammy/Birdie reveal have been tailored to fit the event they place take in.
- Vega, a Spaniard, revealed in Gamescon, an European convention
- R Mika was at PAX, while not American, her wacky and campy wrestling style is very popular in America
- Karin in TGS, explains itself
- Rashid in Dubai Games 15, again, explains itself
- Ken was in SDCC, not only does this convention take place in Murica but Ken is a very well known character, so it was better to reveal him in a general nerd-con where he'd get lots of positive rep
- Necalli was at EVO, which is just about the perfect place to reveal the very first newcomer
Ono had pretty much blatantly said the Brazil Game Show character would be Brazillian, so there's Laura.
NYCC is soon so if Capcom's there and the Sili leak is real, then Alex is probably there.
Idk where to put Urien (again, if the leak is true) but Zen at the Capcom Cup in December seems like a safe bet imo