I wonder if we'll get all three characters tomorrow.
Normally, one would expect them to do a drip-feed release, I.E. one character a month. And in terms of promotional events, there are tie-ins. For example, EVO is in July. So is Fire Emblem's 25th anniversary celebration in Japan, where Sakurai will be a keynote speaker.
However, if all three characters were released tomorrow, they could sell them in a bundle, and have a more dramatic impact where, say, the Street Fighter fans might buy Ryu, but while playing online they'll fight Lucas and Roy, and those encounters may serve as a "suggestive sale" where they find themselves wanting to buy them, as well.
Tomorrow could introduce something akin to "season passes," starting with a Lucas/Roy/Ryu bundle let's say three characters for the price of two, so you effectively get one free and they could reveal a rough release schedule for the next "round" of characters, I.E. Fall 2015.
It'll be interesting to see how they approach this.