[@ShwiggityShwah] I will provide an example, though I will not create a Character Sheet; as of yet.

A rebellious girl, driven beyond simple anger by the loss of her older brother in an accident. Her abilities would manifest, surprisingly, as the ability to create 'light barriers' and to heal the wounds of others. This is reflective of the distance she wishes to keep between herself and the world, now that she has lost what was essentially her 'rock'. The healing would manifest because of her conflict and an intimacy with the pain she feels; a near subconscious desire to prevent others from falling prey to what afflicted her. That feeling, too, ties into the creation of barriers. As she comes to understand this, her abilities may become more potent; or transmogrify in a way.

This is an example, as I said; but I think that it should make clear my idea of how abilities form around the new identity of the Amalgam Soul. These new identities will have lived their own lives, mind you. Until the night of September 3rd, they are essentially mundane.