Kitty didn't die, she just got her memories erased and was hid away after the goddesses helped Neyra fake Kitty's death to fool the human emperor (I guess making a fake dead corpse looking like Kitty was piece of cake for them). The real Kitty was sent to that island because that's the secret hideout the FL inherited from her mom, which her mom had left her in case she ever needed a place to hide from the emperor and/or get a place to live if she ever wanted to give up her adoptive parent's inheritance in favor of her adoptive brother (and that's exactly what happened).
The part with the witch is just flashbacks of their previous life, and how it went after she lost her "soul" due to it being sent to the past, it's like their past life that only they remember (along with the few others who saw the flashback). I think it's supposed to be like a previous life, after which everyone got reborn exactly the same, with the same identity etc etc, so they could do it over.
Or maybe the witch made it so the past selves of FL and ML could receive the "memories" of their future, in order to avoid that future from coming to be.
YOU'RE A LIFESAVER THANK YOUU
I'm so fucking confused, did kitty's soul go the island bc she died?? why do only 5 people live in that mansion/castle. When she woke up in the time where she made the deal with the witch of opportunities, what happened after that. Like it just panned over to current timeline. I'm so confusseddd help