George IV and was next in line to the throne.
Queen. The RF was in a state of panic at one stage as it was looking unlikely that there would be any heirs. George IV's only child died after childbirth, 2 years before Vic was born (had she survived, we would likely have had a Queen Charlotte- another 'new' name for a monarch, though there'd already been a Queen Charlotte, w/o George III), Prince Frederick had long since separated from his wife and had no children and William IV could not produce any healthy, legitimate heirs.
I have a book somewhere which looks into why George IV was so intent on naming her after Alexander I of Russia, but I can't find it! I'm sure it said that he wished she'd reign as Queen Alexandrina. I'm glad she went with Victoria though!