I still like the idea of Rey representing a “vergence in the Force” like Anakin was. It gives Kylo something impactful to say in the hangar scene (although you’d need to create new dialogue wholecloth) and keeps her from being actually related to anybody.

Something like this:

Rey: Why did the Emperor come for me? Why did he want to kill a child? Tell me.
Ren: Because he saw what you would become. You don’t just have power. You’re a vergence in the Force Rey. The most powerful nexus of Force energy since my grandfather. I didn’t want to accept it, but it’s the truth.

For years, I’ve been chasing his power, and all this time it’s been right in front of me. In you. Palpatine fears your power, Rey. We’ll kill him, together, and take the throne.

EDIT: I spent a few hours re-sorting the LEGO Star Wars voiceover lines by character instead of level. This should make relevant lines easier to find: https://drive.google.com/drive/folders/1x9jVm0p8GydqtH1Vvl0SHtfbuIfkUzJV?usp=sharing