The Making of Fire Emblem: 25 Years of Development History contains some fun trivia regarding the series. You can find all the information I translated thus far in one place here.
This is a brief post about how Fire Emblem Awakening started as Fire Emblem: Fin. This makes sense, considering the common knowledge of how Fire Emblem Awakening was to be the last Fire Emblem game if it did not sell well (and indeed was referenced in the same interview).
Below shows the concept work. Originally it was called Fire Emblem Fin and went through plenty of names. The shot below shows “Children from the Brink” as one possibility (Literally, it translates to “Children from the End [of time].” The two silhouettes also resemble Ike on the right and…Stefan? It looks like a silhouette of his official Radiant Dawn artwork, at least. Was it going to be in Tellius? Or maybe a game that had people from all over? We’ll never know. It is just a concept work after all, so that wouldn’t really mean much. If one can guess who the silhouette in the bottom left is, (likely from Tellius), then all the better.