I think that's debatable. It's not rare for characters to have different ages in alternate universes or timeline. So she could have a baby now and it could be Rachel, or not be Rachel, probably regardless of what name they give her. Which is kinda funny cause as you said she could name it Rachel only for the child to grow up being nothing like the other Rachel, or she could name it something else and they actually turn out to be a version of Rachel.
Either way it probably depends on the writer if they agree with my logic or not, so err...