Attack on Titan and Fullmetal Alchemist Brotherhood Crossover

What if Father had another homunculus hidden away in case he was ever in trouble? What if that homunculus was abnormal and able to use alchemy? What if that homunculus knew about a hidden country in a treacherous mountain range, closed off from the rest of the world? What if that homuculus wants to use the country to create a Philosopher's Stone for revenge? If these hypothetical questions were true, we'd have a story that needs a hero to stop that homunculus, and fast! It's been 16 years since Ed and Al have defeated Father, and Ed can't use his alchemy, and Al is recovering from an accident. Enter, Ed's 16 year-old daughter, Trisha(named after mom). She journeys to this isolated, forgotten country to try and save the people there, and finds it's not going to be easy.. With her natural talent for alchemy, feisty character and kick-ass fighting skills, it's time for the next generation to step up!
(Also, I don't own Fullmetal Alchemist, it belongs to Hiromu Arakawa)