Remember this is only a theory of what I assume will happen in season 16. This theory will feature the Meta, Church and Epslion. This is my best guess after rewatching the deaths of the Alpha and Epslion.
They've never mentioned using the fragments Epslion Church left behind so let's assume in their mourning they couldn't handle using the remains of their friend behind in that suit. They might contain pieces and bits of him. His anger, pain, memory and logic. Let's assume they have bits of Church's actual memories.
Being cast aside would drove them crazy but what if they found something like them in the suit. Like the Alpha? With all the nonsense, craziness and bullshit science of the Red Vs Blue universe it's very possible alpha was not wiped out completely by the Electro Magnetic Pulse. Think about it empty shells of one person trapped in the suit.
The Alpha wouldn't be fully complete or well. Glitching and alone for so long inactive with barely any memories. The AI.I.s find him seeking a way to be whole and to move in the Meta suit. They form a fractured, damaged mind with few memories seeking vengeance and achieve metastability. Becoming the new Meta.
But lets assume they don't call him Church but instead parts and bits of his own name or names he briefly remembered. Here are the possible names. Leo., Leonard, L, Church, Alpha, Al or Tex.
Or the amalgamation of Church's remains and of the Alpha don't seek vengeance. But instead they wander with no clear memory seeking friendships. Possibly continue the Church family tradition of being a jackass or being attracted or hunted by badass dangerous women in armor.
They might try to make this a mystery giving clues about the new Meta but don't let them lead you away. Piece things together.