No,
Isabella is still a variant of
Elizabeth. I have a feeling that the idea that
Isabella means "beautiful" has something to do with
Isabella "
Bella" Swan from Twilight.
Bella means "beautiful."
Isabella doesn't. It has the same meaning as
Elizabeth.
It's a lovely name. I'm just putting the information out there because, since you say that you're picking names in part for their meanings, I don't want you to be misinformed.