This makes the original Monster of Frankenstein (usually referred to as just Frankenstein) Frankie's grandfather and his Bride Frankie's grandmother, while Victor Frankenstein is thus her great-grandfather.
Generally in all versions of Monster High, except for the Lisi Harrison books, Frankie is the daughter of Frankenstein's monster and the Bride of Frankenstein's monster, and thus also the granddaughter of Victor Frankenstein. Frankie's mother was the second monster created by Victor Frankenstein and her father was the first.
Ghoulia Yelps is replaced with Ari Hauntington at the end of the movie: "Welcome to Monster High: The Origin Story", and in the Generation 2 webisodes, she is replacing Ghoulia.
There is confirmation that no one in the reboots is being replaced.
Starting out at 15 days old, Frankie is the youngest student at Monster High. There is a generational distinction between Frankie's parents as they appear in the Monster High book series versus the rest of the franchise.
She was built a while back, and on the back of her Picture Day box as in doll box, she says "How many days has it been? As of Welcome to Monster High, her age is "115 days old. In the Monster High books, which are the only source of a name for Frankie's parents (Viktor and Viveka Stein), the two are creations of Frankenstein's Monster and the Bride.
In the series of the Lisi Harrison books, like all series, she is 15 days old.
She is new to the world, and makes friends with Clawdeen, Blue, Lala, and Cleo, and also Melody Carver and Billy Phaidin, who are also fellow RADs, though Melody appears as a human at first.