The two story thing doesn't sound too great to me. I like the first premise and i also think that will be it because Mira Sorvino is not Jill. I think Alice and Jill Should meet because that way you'll have more of a survival feeling. Yes It will be a bit more game like but at some point i think they should meet.
This is the premise from yahoo: (if this is a problem you know with copyrights feel free to edit this Kes)
Picking up where the end of the first movie left off, an elite military agent, Alice (Jovovich), finds herself stranded in the ruins of Raccoon City folowing a virus outbreak which has turned the city's inhabitants into bloodthirsty zombies. Searching for a way to contain the virus, Alice also teams up with other survivors, who include Jill Valentine (the key heroine from the games) (Guillory), who finds herself being hunted down by a massive monster called Nemesis (Mabius) with ties to Alice, and the tendency to moan 'Starrrrssss' a lot. (Oded Fehr plays the head of Umbrella Biohazard Countermeasure Force; Jared Harris plays Dr. Ashford, the wheelchair-bound scientist who developed the "super soldier" formula that caused this whole problem.)
Actually he kinda keeps going "Stars stars stars stars stars stars" as he runs after you (in the game you're jill valentine, A member of S.T.A.R.S. Special Tactics And Rescue Squad). He's a downgraded version of Tyrant that was mass produced by umbrella and sent to eliminate any interference from S.T.A.R.S. team members. In RE 2 a form of nemesis was introduced, but I believe he was called mr. X. Nemesis on the other hand, opens doors and goes through many obstacles to kill S.T.A.R.S. members 😄 I think I remember one time he kinda roars "STAAAAARRSSSSS!!!!" after you escape from him
Nemesis, as close as you ever want to get ~_-