Pretty much what I think will happen when it comes to what we get. In my mind, I think Ike is very likely to return for this game and I don't see any reason why he'd be dropped (and before anyone said lack of recentness or over-representation, someone needs to provide proof that Ike was added because he was the most recent lord and people way over-value "fair" representation). So what I'm thinking is that the third slot is going to be a toss-up between Chrom and Roy. If I had to guess, I'd say Roy mainly due to being planned to return for Brawl and being one of two of the most wanted characters for SSB4 in Japan (along with Mewtwo, both of them even beat Mega Man by a considerable margin and he was the most wanted newcomer in there, but I could see Sakurai going with Chrom as well.
That being said, should we get DLC characters, I really wouldn't be surprised if we get four Fire Emblem characters. I'm almost confident that Marth, Ike and Roy will be planned to return and I also think there's a good chance Sakurai will try to include Chrom as well.