I don’t think the new villager is an avatar. Like in FE11, they’ll add new characters, and a female villager would be a good addition for FE2.
Also, the title “Echoes” makes me think… why?
I think that Echoes will be a series of remakes, they have at least 8 FE to make a series of remakes. This is far fetched, but looking at the logo, “Echoes” is part of the “Fire Emblem” word, and “Shadows of Valentia” looks like a replaceable tittle for future entries.
But, maybe my lack of sleep is making me paranoid.