OmegaXXII
Fire Emblem Lord/ Trophy Hunter
From the looks of it, I'd say Saki's chances are a bit higher due to relevancy, Ray MK is a good choice but just doesn't have what it takes to make it in, he needs "a push" like a new game soon or sudden demand, which in both cases I doubt that happening.I say Saki and Ray MK have the best chances, honestly. The first two are interesting, but I don't see them having a moveset that doesn't feel kind of meh.
As for Gray Fox, I'd rather have no extra 3rd slots for the same series. If it's a different series from the same company, I'm okay with it. Simon Belmont for Smash!
Simon Belmont is good, no great, but I believe Snake will likely to as Konami's rep if Kojima wants him in a second time, Gray Fox was just for lulz, I prefer Liquid Snake, or.....maybe not, just as an Adventure Mode Boss with REX would be epic indeed.