you are pretty close, Zilfer
not every possible situation is covered in the books. if not sure, just wing it until you have time to read over stuff so you don't slow the game down.
yes, good games can be played with just 2 people. it is ideal to have aleast 2 or 3 players, so it is not just you vs her. saying that, most of the SR novels are about one character and the people they happen to interact with. Is it gonna have the same interaction such as Leverage or A-team? no
It is more likely to be like Dark Angel, Dollhouse, or Alias. At the end of the day, one person makes the choice on what they want to do, not a group vote.
gameplay will change with the number of players you have.
on the stealth kill, I would have her roll inflitration, maybe letting her add the net successes to her melee skill, or to use them to keep everyone else from hearing her slit the guy's throat.
at the end of the day, are you both having fun? sounds like it to me
on finding players, either check around your local gaming shop, or try checking out a convention that will have gaming.
good luck to you