@Andorski: Thanks, I was doubtful Jacob would work as a squad leader first time around.
@cap123: To answer your questions:
- Shopping doesn't count against you but doing any kind of side mission will get people killed.
- Yes, you can make it with people on "Normal" loyalty but you might have to turn down the difficulty for it. Make a backup save just in case. I recommend you get either Legion or Tali to full loyalty because you need one of them to be loyal for the last mission.