I am thinking of making Lavinia Vanderboren into another npc my players know rather well--as it turns out she's a sort of background npc I've had turn up now and then, basically a good hearted but impish young woman from a good family who I normally use as a source of rumors and stuff like that. While I'm aware that the first adventure is meant as a starting adventure my players are the sort who like to have associations with previous characters--relatives or former hirelings or whatever--and so it seems like it wouldn't be a big deal to just change the woman's name and say that she recently came into an inheritance following the death of her parents. I'd also never mentioned her brother's name or that of any other relations save name dropping her father as an important merchant/aristocrat.
anyway I can't think of an adverse effect on the game save for this: the number of pc handout things that have Lavinia's name on it or Vanthus' full name. However I can easily make my own handouts.