https://www.youtube.com/watch?v=alUj...em-uploademail
I dont know if this might work but oh well XD:
In the video you can see that the characters can transform thanks to their personas, that are fire emblem characters.
Tiki is featured in this game as an Idol ( the little Green haired girl)
She has appeared as an adult in a recent fire emblem: awakening to be precise. Maybe in order to get fanservice, her transformed version could involve her adult form
Besides there are inconsistencies with the chronology of Fire emblem
Tiki sais in one game she is 3000 years, but only around 600-1000 years occur between that game and awakening so....how did she passed from loli to adult? Maybe the game exploits that gag, and besides, tiki has been brainwashed some other time in the series so it could happen the same way as Peashy from Choujigen Game Neptune.