Rydia will see her biological mother. They loved each other but all Rydia has of her are vague memories of her childhood and since she doesn't remember the woman too much the ghost will be an idealized version of her- too good, too pure, too kind, too perfect. She will probably realize with time that something is off and definitely notice that woman isn't exactly her mother toward the end, mostly because Rydia's mother was far from a perfect angelic figure and because she didn't hesitate to get herself killed when it was time to protect her daughter and the other villagers.

I'm all in for someone wanting to help Rydia kill her ghost, she'll eventually do it herself by the end because 'survival is the priority' (She learnt that from her eidolons) and that thing isn't certainly real... right? It'll still be a trauma...

After her ghost is killed she'll try her best to kill other people's, despite their protests, so... if you need help with yours please just let her know ;)