One thing that was never explained was the source of Ellone's powers. Heres my theory:

Ellone is a sorceress, but doesn't know it. The source of her powers would be her mother. She was gunned down by Galbadian Soldiers. Why would a sorceress be killed so easily? Some sorceresses try to keep a low profile and live as close to normal lives as they can. Ellone's biological mother likely didn't train her powers, for fear of retribution from a public scared stiff of Sorceresses. When she was killed, the only girl available to inherit her powers was Ellone.

Given she was little, she might not have understood what her powers meant, and given that the public might have not known the Ellone's mother was a sorceress, everyone, Ellone included, might have written it off as a natural gift.

Given she only knows about her power to make people relive other people's memories, she might have only trained those powers, and not have tried combat magic.

Given the common thread of time magic, one might be able to conclude that Ultimecia is in Ellone's succession of witches. Junction Machine Ellone might not be able to allow Ultimecia to directly control people, but perhaps it might stack with the natural powers Ellone once had that Ultimecia has now, which might be enough for that.

I dunno, its just a theory though.