Well, we've known about her resembling someone else since the first chapter; Sonia called her Lavie upon first seeing her:
https://mangadex.org/chapter/0be4340c-9a6c-4601-9b14-0c1ef78621b5/18 So this is the second time someone thinks she looks like Lavie.
But oddly enough, Howard didn't make any remark on her looks even though he must have also known the person called Lavie. No one else in the village seems to know her either so it doesn't seem that Lavie was an inhabitant of this village. If she was, then Lavie may have been older since the children didn't know of any child looking like Susie.
But yeah, I doubt she's reincarnated in someone else's body in the middle of the mountains. I mean, if this Lavie passed away, I expect they would have held a funeral. This new person seems quite certain that she can't be Lavie even if she looks like her. Well hopefully we'll learn who this Lavie actually is in the next chapter.