To clarify a little on the Elluka thing:
According to Sickle, she is the real Elluka Clockworker, Sorceress of Time.
However, she also isn't Elluka Clockworker. And he won't explain that any further.
One thing that does seem clear though is that she is not the same person as Ma, as she is taken away to be executed. She also is not really acting like Ma during the story (or her past self as Elluka, for that matter).
There may be clarification on this later.