There is one thing you are forgetting (or unaware of): Fire Emblem Awakening is the best selling game in the series is easily the most popular. It makes a lot of sense for characters from this game to appear in Smash, even if they are "one-shot" characters.As much as I want to bash this, it brings up a great point.
From what I know of the FE universe(i.e. very little), Lucina and Robin were only in one game, similar to Anthony. Granted, Anthony is no where NEAR as requested as Ridley, but it's till concerning that Lucina and Robin, who were less requested than Chrom, made the cut.
What do you all think?
Metroid Other M is easily one of the least popular Metroid games and the sales were nothing to be happy about (thank ****ing god), so putting Anthony Higgs, Adam or any Other M character in Smash is something I can't really see happening.